Toggle each character in a string in C++

Understanding Character Toggling

Character toggling means converting uppercase letters to lowercase and vice versa.

We will explore three different methods to toggle characters in a string using C++.

Method 1: Using a Loop

This method iterates through the string and toggles each character.

#include <iostream>
#include <cctype>
using namespace std;

void toggle_case(string &str) {
    for (char &ch : str) {
        if (islower(ch))
            ch = toupper(ch);
        else if (isupper(ch))
            ch = tolower(ch);
    }
}

int main() {
    string str;
    cout << "Enter a string: ";
    getline(cin, str);
    toggle_case(str);
    cout << "Toggled string: " << str << endl;
    return 0;
}
            

Method 2: Using Recursion

This method toggles characters recursively.

#include <iostream>
#include <cctype>
using namespace std;

void toggle_recursive(string &str, int index) {
    if (index == str.length()) return;
    if (islower(str[index]))
        str[index] = toupper(str[index]);
    else if (isupper(str[index]))
        str[index] = tolower(str[index]);
    toggle_recursive(str, index + 1);
}

int main() {
    string str;
    cout << "Enter a string: ";
    getline(cin, str);
    toggle_recursive(str, 0);
    cout << "Toggled string: " << str << endl;
    return 0;
}
            

Method 3: Using Bitwise Operations

This method toggles characters using bitwise XOR operation.

#include <iostream>
using namespace std;

void toggle_bitwise(string &str) {
    for (char &ch : str) {
        ch ^= 32;
    }
}

int main() {
    string str;
    cout << "Enter a string: ";
    getline(cin, str);
    toggle_bitwise(str);
    cout << "Toggled string: " << str << endl;
    return 0;
}