🔀 C++ Conditional Statements: if-else and switch

❓ Why Use Conditions?

Conditions allow your program to choose different paths based on logical checks. Think of it like this:

“If the user is above 18, allow access. Otherwise, deny access.”

✅ if, else if, and else

🧠 Syntax:

if (condition) {
    // code block
} else if (another_condition) {
    // another block
} else {
    // fallback block
}

📌 Example:

int age;
cin >> age;

if (age >= 18) {
    cout << "Access granted.";
} else {
    cout << "Access denied.";
}

🧠 else if: Multiple Conditions

int marks;
cin >> marks;

if (marks >= 90) {
    cout << "Grade: A";
} else if (marks >= 80) {
    cout << "Grade: B";
} else if (marks >= 70) {
    cout << "Grade: C";
} else {
    cout << "Grade: F";
}

🪓 switch Statement

Use switch When you want to compare a single variable against multiple fixed values (like menu choices, grades, days of the week).

🧠 Syntax:

switch (expression) {
    case value1:
        // code
        break;
    case value2:
        // code
        break;
    default:
        // fallback code
}

📌 Example:

int day;
cin >> day;

switch (day) {
    case 1: cout << "Monday"; break;
    case 2: cout << "Tuesday"; break;
    case 3: cout << "Wednesday"; break;
    default: cout << "Invalid day";
}

⚠️ if vs. switch – When to Use What?

🚫 Common Mistakes

❌ Forgetting to use break in switch:

case 1: cout << "One";  // will fall through to next case

❌ Using switch with a string or float (not allowed in C++)
❌ Putting a semicolon after if condition:

if (x > 0);  // ❌ This ends the if statement early

💼 Task for You

🔧 Task:

1. Take a user’s exam score as input.

2. Use if-else to print their grade based on:

   • 90+: A

   • 80-89: B

   • 70-79: C

   • Else: F

3. Then take a number between 1–7 as input and use switch to print the corresponding day name.

🖨️ Sample Output:

Enter your score: 85
Grade: B

Enter day number (1-7): 3
Day: Wednesday

🎯 What’s Next?

With conditional logic mastered, you're ready to repeat actions using loops! In the next part, we’ll cover for, while, and do-while Loops to add repetition to your programs.

📍Next up: Part 9 – Loops in C++

✨ Follow the Series

C++ Zero to Hero is your step-by-step journey to becoming confident in C++. From the very basics to algorithms and problem-solving — one topic at a time.

👣 Stay consistent. Practice every task. And soon, you’ll be writing real-world C++ applications like a pro.