C++ String Exercises: Change the case of each character of a given string

Last update on April 11 2025 12:47:44 (UTC/GMT +8 hours)

13. Toggle Case of Each Character in a String

Write a C++ program to change the case (lower to upper and upper to lower cases) of each character in a given string.

Visual Presentation:

Sample Solution:

C++ Code :

#include <iostream> // Include input/output stream library
#include <string> // Include string library for string operations
#include <cctype> // Include cctype library for character handling functions

using namespace std; // Using the standard namespace

// Function to change the case of characters in a string
string change_Case(string text) {

    // Loop through each character in the string
    for (int x = 0; x < text.length(); x++)
    {
        // Check if the character is uppercase
        if (isupper(text[x]))
        {
            text[x] = tolower(text[x]); // Convert uppercase to lowercase
        }
        else
        {
            text[x] = toupper(text[x]); // Convert lowercase to uppercase
        }
    }

    return text; // Return the modified string with changed cases
}

// Main function
int main() {

    // Output original strings and their modified versions after changing cases
    cout << "Original string: Python, After changing cases-> "<< change_Case("Python") << endl;
    cout << "Original string: w3resource,  After changing cases-> "<< change_Case("w3resource") << endl;
    cout << "Original string: AbcdEFH Bkiuer,  After changing cases-> "<< change_Case(" AbcdEFH Bkiuer") << endl;

    return 0; // Return 0 to indicate successful completion
}

Sample Output:

Original string: Python, After changing cases-> pYTHON
Original string: w3resource,  After changing cases-> W3RESOURCE
Original string: AbcdEFH Bkiuer,  After changing cases->  aBCDefh bKIUER

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C++ program to swap the case of every letter in a string using ASCII arithmetic.
• Write a C++ program that reads a string and converts uppercase letters to lowercase and vice versa using a loop.
• Write a C++ program to toggle the case of each character in a string without using any library functions.
• Write a C++ program that processes an input string and prints the string with each alphabet character's case reversed.

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Previous C++ Exercise: Insert a dash between two odd numbers in a string.
Next C++ Exercise: Find the numbers in a string and calculate the sum.