Day 6 but Day 4 of Recursion

Hello! everyone, it's nice to interact and share my experiences with you. I hope you like my blogs. As we were going through the topics of recursion, we also tried to solve a few of the questions with the help of recursion. However, solving only a few problems won't help us fully grasp the concept of recursion. So again today we'll be going via the questions of recursions.

Reversing a string = String isn't a datatype, as many may confuse it. The string is a collection of characters, however, all the string characters are accessed using the concept of indexing just like arrays.

#include<bits/stdc++.h>
using namespace std;

void reverseString(string& str, int i, int j){

    //base case
    if (i >= j)
    {
        return;
    }
    swap(str[i], str[j]);
    i++;
    j--;

    reverseString(str, i, j);
}

int main(){
    string s;

    cout << "Enter string : ";
    cin >> s;

    reverseString(s, 0, s.length()-1);

    cout << "Reversed String = " << s;

    return 0;
}

Palindrome = When a string id equal to the reverse of itself, then this case of string is known as Palindrome. Given below is the code you can used to check if a string is Palindrome or not.

#include<bits/stdc++.h>
using namespace std;

bool checkPalindrome(string str, int i, int j){
    //base case
    if(i >= j){
        return true;
    }
    if(str[i] != str[j]){
        return false;
    }
    else{
        return checkPalindrome(str, i+1, j-1);
    }
}
int main(){
    string s;

    cout << "Enter string : ";
    cin >> s;

    bool isPalindrome = checkPalindrome(s, 0, s.length()-1);
    if(isPalindrome){
        cout << "It's a Palindrome";
    }
    else{
        cout << "It's not a Palindrome";
    }

    return 0;
}

• Power of number = In mathematics, we're sometimes asked to calculate the power of a number like 2^3, 3^11, 5^1/2. Follow the code to understand it properly: -

    #include<bits/stdc++.h>
    using namespace std;
  
    int power(int a, int b){
  
        if (b == 0)
        {
            return 1;
        }
        if(b == 1){
            return a;
        }
  
        int ans = power(a, b/2);
  
        if(b%2 == 0){
            return ans*ans;
        }
        else{
            return a*ans*ans;
        }    
    }
  
    int main(){
        int a, b;
  
        cout << "Enter a & b: ";
        cin >> a >> b;
  
        int ans = power(a, b);
  
        cout << "Answer = " << ans << endl;
  
        return 0;
    }