Day 4: Deep Dive into Java Conditionals, Logical Operators & Loops — Step-by-Step Practice and Programs

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1️⃣ WeatherConditionChecker — Logical Operators with User Input

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What This Program Does

• Takes two inputs from the user: temperature and whether it’s sunny.

• Checks if temperature is between 0°C and 30°C and if it’s sunny or not.

• Prints messages about the weather based on these conditions.

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Why This Program Is Important

Understanding how to combine multiple conditions with logical operators (&&, ||, !) is fundamental in programming. It helps you build programs that can make complex decisions just like humans do.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;  // Import Scanner class for input

public class WeatherConditionChecker {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);  // Create Scanner object to read input

        System.out.print("Enter the temperature: ");  // Ask user for temperature
        double temp = scanner.nextDouble();  // Read the temperature as a decimal (e.g., 25.5)

        System.out.print("Is it sunny? (true/false): ");  // Ask if it’s sunny
        boolean isSunny = scanner.nextBoolean();  // Read boolean input (true or false)

        // Check if temperature is between 0 and 30 AND it is sunny
        if (temp <= 30 && temp >= 0 && isSunny) {
            System.out.println("The weather is good.");  // First message if all true
            System.out.println("It is Sunny outside.");  // Second message for sunny
        } 
        // Else if temperature is in range but NOT sunny
        else if (temp <= 30 && temp >= 0 && !isSunny) {
            System.out.println("The weather is good.");  // Weather still good
            System.out.println("It is Cloudy outside.");  // Different message for cloudy
        } 
        // Else if temperature outside 0-30 range (either below 0 or above 30)
        else if (temp > 30 || temp < 0) {
            System.out.println("The weather is bad.");  // Weather is bad here
        }

        scanner.close();  // Close Scanner to free resources
    }
}

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Line-by-Line Breakdown

• import java.util.Scanner;: This allows us to read input from the keyboard.

• Scanner scanner = new Scanner(System.in);: Creates a Scanner object named scanner to read user input.

• System.out.print("Enter the temperature: ");: Prints prompt without a newline.

• double temp = scanner.nextDouble();: Reads the next decimal number typed by the user and stores in temp.

• System.out.print("Is it sunny? (true/false): ");: Asks user for sunny info.

• boolean isSunny = scanner.nextBoolean();: Reads boolean input (true or false).

• if (temp <= 30 && temp >= 0 && isSunny): Checks if temp between 0 and 30 inclusive AND it’s sunny.

• System.out.println("The weather is good.");: Prints “weather good” message.

• System.out.println("It is Sunny outside.");: Prints “sunny” message.

• else if (temp <= 30 && temp >= 0 && !isSunny): Checks if temp in range but NOT sunny (! means NOT).

• else if (temp > 30 || temp < 0): Checks if temp outside range (above 30 or below 0).

• scanner.close();: Closes the scanner object to free system resources.

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Why These Conditions?

• && (AND) ensures all conditions must be true to execute the block.

• || (OR) means if any condition is true, execute that block.

• ! negates boolean (true becomes false and vice versa).

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Important Notes & Practical Tips

• Always close your Scanner when done to prevent resource leaks.

• Input for scanner.nextBoolean() must be exactly true or false, or it will throw an exception.

• Logical operators are the backbone of decision making in programming.

• Make sure you understand the precedence: ! > && > || (NOT has higher priority than AND, which has higher priority than OR).

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Quick Quiz for Yourself

• What happens if the temperature is 25 and user inputs false for sunny?

• Why can’t we just use one if condition without else if here?

• How would you modify the program to also consider rain or snow?

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2️⃣ UsernameValidator — String Validation Using Conditions

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What This Program Does

• Takes username input from the user.

• Checks if username is between 4 and 12 characters.

• Checks if username contains spaces or underscores, which are not allowed.

• If valid, welcomes the user; otherwise, shows error messages.

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Why This Program Is Important

Validating user input is essential for security and data integrity. This example shows how to check string length and substring presence.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class UsernameValidator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter your username: ");
        String username = scanner.nextLine();  // Reads entire line as username

        // Check username length outside valid range
        if (username.length() < 4 || username.length() > 12) {
            System.out.println("Username must be between 4-12 characters.");
        } 
        // Check if username contains spaces or underscores
        else if (username.contains(" ") || username.contains("_")) {
            System.out.println("Username must not contain any whitespaces or underscores.");
        } 
        // Username passes all checks
        else {
            System.out.println("WELCOME " + username);
        }

        scanner.close();
    }
}

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Line-by-Line Breakdown

• String username = scanner.nextLine();: Reads full user input including spaces until Enter is pressed.

• username.length(): Returns how many characters the username has.

• username.contains(" "): Checks if username has any space.

• username.contains("_"): Checks if username has underscores.

• Logical OR || means if either condition is true, username is invalid.

• The last else is executed only if all previous conditions fail.

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Why Use These Checks?

• Length limits protect from overly short or long usernames.

• Spaces and underscores might not be allowed in your username rules.

• Using string methods keeps validation simple and readable.

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Important Notes & Practical Tips

• You can chain multiple validation rules easily with logical operators.

• For more complex validation, consider regular expressions (regex).

• User feedback should be clear — tell users exactly what’s wrong.

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Quick Quiz

• What happens if username is “abc”?

• How would you allow underscores but not spaces?

• Can .contains() check for multiple characters or patterns? (Hint: No, for complex pattern use regex)

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3️⃣ NamePromptWhile — Looping Until Non-Empty Input

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What This Program Does

• Continuously prompts the user for their name.

• Doesn’t proceed until the user enters something (non-empty input).

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Why This Program Is Important

Sometimes you need mandatory input — you must force the user to enter valid data before moving on.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class NamePromptWhile {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String name = "";  // Start with empty string

        // While the name is empty, keep asking for input
        while (name.isEmpty()) {
            System.out.print("Enter your name: ");
            name = scanner.nextLine();  // Reads user input
        }

        System.out.println("Hello " + name);  // Greet the user

        scanner.close();
    }
}

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Why Does This Work?

• name.isEmpty() returns true if string length is zero.

• Loop keeps running as long as user enters an empty string.

• When user enters any character(s), .isEmpty() returns false and loop exits.

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Important Notes

• Using .isEmpty() is safer than checking name == "" because string equality uses .equals() in Java.

• You can use .trim() if you want to avoid inputs with only spaces.

• Always validate input before processing.

Quick Quiz

• How would you reject input with only spaces?

• What would happen if you forgot to update name inside the loop?

• How is while different from do-while?

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4️⃣ GameQuitLoop — User-Controlled Loop Exit with While Loop

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What This Program Does

• Keeps asking the user to press Q to quit a game.

• The loop continues until the user enters Q (case-insensitive).

• Prints a message when the user exits the game.

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Why This Program Is Important

User-controlled loops are very common. Here, we learn to:

• Accept string input.

• Normalize user input (case-insensitive comparison).

• Use a loop that depends on user input to terminate.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class GameQuitLoop {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String response = "";  // Initialize empty string for user input

        // Loop keeps running as long as response is NOT "Q"
        while (!response.equals("Q")) {
            System.out.print("You are in a Game!! Press Q to quit: ");
            response = scanner.nextLine().toUpperCase();  // Convert input to uppercase
        }

        System.out.println("You have exited the game!!");  // Exit message

        scanner.close();
    }
}

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Line-by-Line Explanation

• String response = "";: Initialize response to empty, so loop starts.

• while (!response.equals("Q")): Loop continues while response is not exactly "Q".

• scanner.nextLine().toUpperCase(): Reads full user input and converts it to uppercase so input is case-insensitive (q or Q both accepted).

• When the user inputs "Q", !response.equals("Q") becomes false and loop stops.

• Then program prints exit message and closes scanner.

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Important Concepts

• .equals() is used to compare strings in Java, not ==.

• .toUpperCase() helps us avoid writing multiple checks for both "q" and "Q".

• Using ! (NOT) operator negates the boolean condition — this is common in loops waiting for a specific exit input.

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Practical Tips

• For better UX, consider trimming input before converting case: scanner.nextLine().trim().toUpperCase()

• If you want to accept multiple commands to quit, you can use OR (||) in the while condition.

• Always prompt the user clearly about how to exit the loop.

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Quick Quiz

• What happens if the user enters just Enter without any letter?

• How would you modify the code to also accept lowercase 'q' without toUpperCase()?

• Why can’t we use response == "Q" in Java to compare strings?

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5️⃣ AgeValidationWhile — Input Validation with While Loop

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What This Program Does

• Asks the user to input their age.

• If the age entered is negative, it keeps asking again until a valid (non-negative) age is entered.

• Finally, prints the valid age.

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Why This Program Is Important

Input validation is essential for reliable programs. This example shows how to force the user to provide valid numeric input.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class AgeValidationWhile {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int age;

        System.out.print("Enter your age: ");
        age = scanner.nextInt();  // Read initial age input

        // If age is negative, ask repeatedly until valid input
        while (age < 0) {
            System.out.print("Your age can't be negative!!! Enter your age again: ");
            age = scanner.nextInt();
        }

        System.out.println("You are " + age + " years old.");

        scanner.close();
    }
}

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Line-by-Line Explanation

• int age;: Declare variable for user age.

• age = scanner.nextInt();: Read integer input.

• while (age < 0): Check if age is negative, if so repeat block.

• Inside loop, prompt again and read new input.

• When age is zero or positive, loop exits and program continues.

• Print valid age.

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Important Concepts

• while loops check the condition before running the loop body.

• This ensures that the input is validated before proceeding.

• Prevents illogical data like negative ages.

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Practical Tips

• If you want to be super safe, handle exceptions when user inputs non-integers (try-catch blocks).

• Add a maximum age limit if needed (like age > 120).

• Always provide clear instructions for re-entering invalid data.

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Quick Quiz

• What happens if the user enters a negative number twice?

• How can you ensure the program doesn’t crash if user inputs a letter instead of a number?

• How would you validate the age to be between 0 and 120?

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6️⃣ AgeValidationDoWhile — Input Validation with Do-While Loop

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What This Program Does

• Same as the previous one: ensures user enters a valid age (non-negative).

• But uses a do-while loop, which executes the input prompt at least once before checking.

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Why This Program Is Important

do-while loops are great when you want the code inside the loop to run at least once, even if the condition is false initially.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class AgeValidationDoWhile {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int age;

        do {
            System.out.print("Enter your age: ");
            age = scanner.nextInt();

            if (age < 0) {
                System.out.println("Your age can't be negative!!!");
            }
        } while (age < 0);  // Repeat if age is invalid

        System.out.println("You are " + age + " years old.");

        scanner.close();
    }
}

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Line-by-Line Explanation

• do { ... } while(condition);: Loop body runs first, then condition is checked.

• Prompts for age and reads input.

• If age < 0, prints error message.

• Loop repeats until user enters a valid age.

• After loop, prints valid age.

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Differences from Previous Program

• while loop checks condition before running.

• do-while guarantees prompt runs at least once — useful for mandatory input scenarios.

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Practical Tips

• do-while is perfect for menu-driven programs where the menu must show before user chooses.

• This style avoids duplicating input prompt outside and inside the loop.

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Quick Quiz

• What if user enters valid age first time? Does do-while still work correctly?

• How is the user experience different with do-while vs while?

• Can do-while loops cause infinite loops? How to avoid that?

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7️⃣ NumberRangeWhile — Validating Input in a Range Using While Loop

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What This Program Does

• Forces user to input a number between 1 and 10.

• If input is outside this range, keeps asking until valid.

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Why This Program Is Important

Range checking is common, e.g., for menu choices or numeric input.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class NumberRangeWhile {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int number = 0;  // Initialize with invalid value

        // Continue looping while number is less than 1 or greater than 10
        while (number < 1 || number > 10) {
            System.out.print("Enter a number between 1-10: ");
            number = scanner.nextInt();
        }

        System.out.println("You hit " + number);

        scanner.close();
    }
}

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Line-by-Line Explanation

• int number = 0; starts with invalid value to enter loop.

• while (number < 1 || number > 10): condition is true if number out of range.

• Prompt user each time inside loop.

• Once valid number entered, loop ends.

• Print confirmation.

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Important Concepts

• Use || (OR) for range checking: number must be inside boundaries.

• Loop ensures user cannot proceed without valid input.

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Practical Tips

• Use clear messages to inform the user of valid input range.

• Consider input type safety (handle non-integers).

• Combine with try-catch for robust input handling.

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Quick Quiz

• What happens if user inputs 0?

• How would you change this program to accept only even numbers between 2 and 20?

• What is the difference between && and || in this context?

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8️⃣ NumberRangeDoWhile — Range Validation with Do-While Loop

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What This Program Does

• Same as previous program but uses do-while.

• Ensures the prompt appears at least once.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class NumberRangeDoWhile {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int number;

        do {
            System.out.print("Enter a number between 1-10: ");
            number = scanner.nextInt();
        } while (number < 1 || number > 10);  // Repeat if out of range

        System.out.println("You picked " + number);

        scanner.close();
    }
}

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Line-by-Line Explanation

• The do block runs first and prompts for input.

• After input, the condition checks if number is invalid.

• If invalid, loops again; else, proceeds.

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Why Use do-while?

When you want the prompt to show before validation — guarantees prompt always shows.

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Practical Tips

• Use this pattern when initial user input is mandatory.

• Helps reduce code duplication (vs. prompting outside and inside while).

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Quick Quiz

• Can this program accept zero?

• How is this program behaviorally different from the while loop version?

• What happens if the user inputs non-integer?

9️⃣ NumberGuessingGame — Interactive Number Guessing with Random Numbers & Feedback

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What This Program Does

• Generates a random number between 1 and 100.

• Lets the user guess the number repeatedly.

• Gives feedback whether guess is too low or too high.

• Counts the number of attempts until the correct guess.

• Congratulates the user on success.

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Why This Program Is Important

This program combines:

• Random number generation.

• User input with validation.

• Control flow using do-while loop.

• Conditional feedback to guide user.

• Counting attempts to track progress.

It's a classic beginner's project demonstrating many core programming concepts.

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Detailed Code Explanation

javaCopyEditimport java.util.Random;
import java.util.Scanner;

public class NumberGuessingGame {
    public static void main(String[] args) {
        Random random = new Random();  // For generating random numbers
        Scanner scanner = new Scanner(System.in);

        int guess;
        int attempts = 0;
        int min = 1;
        int max = 100;

        int randomNumber = random.nextInt(min, max + 1);  // Generates 1 to 100 inclusive

        System.out.println("Welcome to the Number Guessing Game!");
        System.out.printf("Guess a number between %d - %d:\n", min, max);

        do {
            System.out.print("Enter a guess: ");
            guess = scanner.nextInt();
            attempts++;  // Increase attempt count

            if (guess < randomNumber) {
                System.out.println("Too low! Try again.");
            } else if (guess > randomNumber) {
                System.out.println("Too high! Try again.");
            } else {
                System.out.println("Correct!!! The number was " + randomNumber);
                System.out.println("Number of attempts: " + attempts);
            }
        } while (guess != randomNumber);

        System.out.println("Congratulations!!! You guessed the right number!!!");

        scanner.close();
    }
}

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Line-by-Line Explanation

• Random random = new Random(); sets up random number generator.

• random.nextInt(min, max + 1) generates number between min and max inclusive.

• attempts keeps track of user guesses.

• do-while loop continues until guess matches random number.

• Inside loop, user inputs guess, attempts increment, and feedback prints.

• When correct, prints success message and number of tries.

• Closes scanner to avoid resource leak.

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Important Concepts

• Random number generation with nextInt(int origin, int bound).

• do-while loop for guaranteed initial input prompt.

• Conditional checks (if-else) give helpful hints.

• Tracking variables (attempts) enhance user experience.

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Practical Tips

• Handle invalid inputs (e.g., numbers out of range or non-integers) for better UX.

• Add option to quit anytime or reveal the number after certain tries.

• You could improve by making it multiplayer or time-limited.

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Quick Quiz

• Why use do-while instead of while here?

• What happens if the user inputs 0 or 101?

• How would you modify the program to allow hints like “within 10 of the number”?

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🔟 ForLoopCounter — Counting with For Loop & User-Defined Range

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What This Program Does

• Asks the user for a number.

• Counts from 1 up to that number.

• Prints each number on a new line.

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Why This Program Is Important

This is a simple but essential exercise to understand:

• How for loops work.

• Loop initialization, condition, and increment.

• Taking user input to control loop behavior.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class ForLoopCounter {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter how many times you want to loop: ");
        int max = scanner.nextInt();  // User input controls loop count

        for (int i = 1; i <= max; i++) {  // Loop from 1 to max
            System.out.println(i);
        }

        scanner.close();
    }
}

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Line-by-Line Explanation

• User inputs max for upper limit.

• for loop starts with i = 1.

• Continues looping as long as i <= max.

• i++ increments i by 1 each iteration.

• Prints i each loop.

• When i exceeds max, loop ends.

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Important Concepts

• for loops combine initialization, condition, and update in one line.

• Using user input in loops adds flexibility.

• Counting from 1 is common; can be changed to 0 or any start.

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Practical Tips

• Validate user input to ensure max > 0.

• You can change loop to count down by modifying init, condition, and update.

• Use loops for repetitive tasks and generating sequences.

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Quick Quiz

• What happens if user inputs 0 or a negative number?

• How to modify this to print only even numbers between 1 and max?

• What if you want to print numbers backwards?

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1️⃣1️⃣ CountdownTimer — For Loop with Delay and Countdown Display

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What This Program Does

• Asks user how many seconds to count down from.

• Prints the countdown numbers one per second.

• After reaching zero, prints a celebratory message.

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Why This Program Is Important

This program teaches:

• Using for loops to count backward.

• Delaying program execution (Thread.sleep).

• Exception handling with throws InterruptedException.

• Combining user input with timing control.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class CountdownTimer {
    public static void main(String[] args) throws InterruptedException {
        Scanner scanner = new Scanner(System.in);

        System.out.print("How many seconds to countdown from?: ");
        int start = scanner.nextInt();

        // Loop counts down from start to 0
        for (int i = start; i >= 0; i--) {
            System.out.println(i);
            Thread.sleep(1000);  // Pause 1 second (1000 ms)
        }

        System.out.println("Happy New Year!!");

        scanner.close();
    }
}

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Line-by-Line Explanation

• throws InterruptedException needed because Thread.sleep() can be interrupted.

• for loop starts at user input value and decrements i until zero.

• Thread.sleep(1000) pauses execution for 1 second to simulate real-time countdown.

• After loop ends, prints celebration message.

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Important Concepts

• Using loops to control timing events.

• Handling checked exceptions (InterruptedException).

• Real-world applications: timers, clocks, delays.

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Practical Tips

• Validate user input (non-negative seconds).

• Use try-catch block for better exception handling.

• Can be expanded to trigger events at zero.

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Quick Quiz

• What if the user inputs a negative number?

• What happens if the program is interrupted during sleep?

• How to change delay to half a second?

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1️⃣2️⃣ BreakContinueDemo — Controlling Loop Flow with break and continue

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What This Program Does

• Demonstrates two important loop control statements: break and continue.

• First loop stops printing numbers when it reaches 5 (break).

• Second loop skips printing number 5 but continues the rest (continue).

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Why This Program Is Important

Understanding break and continue lets you:

• Exit loops early when a condition is met.

• Skip specific iterations without exiting the loop.

• Control loops with fine granularity.

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Detailed Code Explanation

javaCopyEditpublic class BreakContinueDemo {
    public static void main(String[] args) {

        System.out.println("Using break:");
        for (int i = 0; i <= 10; i++) {
            if (i == 5) {
                break;  // Exit loop immediately when i is 5
            }
            System.out.print(i + " ");
        }
        System.out.println("\n");

        System.out.println("Using continue:");
        for (int j = 0; j <= 10; j++) {
            if (j == 5) {
                continue;  // Skip printing 5, continue next iteration
            }
            System.out.print(j + " ");
        }
    }
}

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Line-by-Line Explanation

• First loop: prints 0 to 4, then breaks at 5, ending loop early.

• Second loop: skips printing 5 but prints all other numbers.

• break completely exits the loop.

• continue skips current iteration only.

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Important Concepts

• Use break to exit loops prematurely.

• Use continue to skip specific iterations.

• Helps avoid nested if-statements and improve readability.

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Practical Tips

• Use break carefully in nested loops.

• Avoid infinite loops with proper break conditions.

• continue is useful when filtering items in loops.

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Quick Quiz

• What happens if you remove break?

• Can continue be used with while loops?

• How would you skip all even numbers using continue?

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1️⃣3️⃣ NestedLoopsDemo — Nested For Loops to Print Patterns

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What This Program Does

• Uses nested loops to print three rows.

• Each row contains nine copies of the row number.

• Resulting in a 3x9 block of numbers.

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Why This Program Is Important

Nested loops are vital for:

• Working with multi-dimensional data.

• Printing tables, patterns, and grids.

• Understanding loop control and scope.

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Detailed Code Explanation

javaCopyEditpublic class NestedLoopsDemo {
    public static void main(String[] args) {

        for (int i = 1; i <= 3; i++) {         // Outer loop controls rows
            for (int j = 1; j <= 9; j++) {     // Inner loop controls columns
                System.out.print(i + " ");     // Print current row number
            }
            System.out.println();               // Newline after each row
        }
    }
}

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Line-by-Line Explanation

• Outer loop i runs 3 times (rows).

• Inner loop j runs 9 times (columns) per outer iteration.

• Prints i nine times per line.

• After inner loop, prints newline to start next row.

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Important Concepts

• Inner loops complete fully for each iteration of outer loop.

• Printing with spaces to format output.

• Loop variables are local to their loops.

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Practical Tips

• Modify ranges to change grid size.

• Print different characters for patterns.

• Useful in GUI grids or matrix operations.

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Quick Quiz

• How would you print a multiplication table using nested loops?

• What changes if you swap inner and outer loops?

• How can nested loops be used to traverse 2D arrays?

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1️⃣4️⃣ SymbolGridPrinter — User-Defined Grid of Symbols with Nested Loops

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What This Program Does

• Asks the user for number of rows, columns, and a symbol.

• Prints a grid of that symbol with specified dimensions.

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Why This Program Is Important

Combines:

• User input.

• Nested loops for rows and columns.

• Printing characters multiple times.

A practical pattern-building program.

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Detailed Code Explanation

javaCopyEditimport java.util.Scanner;

public class SymbolGridPrinter {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter the number of rows: ");
        int rows = scanner.nextInt();

        System.out.print("Enter the number of columns: ");
        int columns = scanner.nextInt();

        System.out.print("Enter the symbol: ");
        char symbol = scanner.next().charAt(0);  // Reads first char of user input

        for (int i = 1; i <= rows; i++) {       // Loop over rows
            for (int j = 1; j <= columns; j++) { // Loop over columns
                System.out.print(symbol);         // Print symbol without newline
            }
            System.out.println();                 // Newline after each row
        }

        scanner.close();
    }
}

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Line-by-Line Explanation

• Reads rows and columns as integers.

• Reads a symbol character (char) from user input.

• Outer loop runs rows times.

• Inner loop prints columns times per row.

• After each row, prints newline to move to next line.

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Important Concepts

• Nested loops for 2D printing.

• Using scanner.next().charAt(0) to get a single character.

• Input-driven dynamic patterns.

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Practical Tips

• Validate inputs for positive numbers.

• Use different symbols to create patterns.

• Can be extended to print different characters per row or column.

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Quick Quiz

• How to modify code to print row numbers instead of symbols?

• How would you create a checkerboard pattern?

• Can you print hollow rectangles using nested loops?

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Summary of Today’s Concepts

• Logical operators: combine multiple conditions for decision making.

• Input validation: loops (while, do-while) ensure correct input.

• Control flow modifiers: break and continue control loop execution.

• Loops: for, while, do-while loops used for repetition.

• Nested loops: create complex output patterns and grids.

• User interaction: combine input with loops for interactive programs.