Lecture 129:- Changing Case of a String

In C and C++, you can change the case of a string by converting the characters to uppercase or lowercase. The standard library provides functions for this purpose. Here are examples of how to change the case of a string in both C and C++:

Changing Case of a String (C++):

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#include <iostream> #include <string> #include <algorithm> int main() {    std::string str = "Hello, World!";        // Convert to uppercase    std::transform(str.begin(), str.end(), str.begin(), ::toupper);    std::cout << "Uppercase string: " << str << std::endl;    // Convert to lowercase    std::transform(str.begin(), str.end(), str.begin(), ::tolower);    std::cout << "Lowercase string: " << str << std::endl;    return 0; }

Changing Case of a String (C):

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#include <stdio.h> #include <ctype.h> #include <string.h> void toUppercase(char* str) {    while (*str) {        *str = toupper(*str);        str++;    } } void toLowercase(char* str) {    while (*str) {        *str = tolower(*str);        str++;    } } int main() {    char str[] = "Hello, World!";        // Convert to uppercase    toUppercase(str);    printf("Uppercase string: %s\n", str);    // Convert to lowercase    toLowercase(str);    printf("Lowercase string: %s\n", str);    return 0; }

In both examples, we demonstrate converting the string "Hello, World!" to uppercase and then to lowercase.

For C++, the std::transform function is used with the ::toupper and ::tolower functions from the <cctype> header to convert each character of the std::string object to uppercase and lowercase, respectively.

For C, we define two functions, toUppercase and toLowercase, which use the toupper and tolower functions from the <ctype.h> header to convert each character of the character array to uppercase and lowercase, respectively.

The output of the program will be:

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Uppercase string: HELLO, WORLD! Lowercase string: hello, world!

Both approaches will correctly change the case of the given string. Choose the one that suits your preference and the programming language you are using.