Example: String to Uppercase using toupper() in C

C
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C#
Java
Python
PHP
// String to Uppercase using toupper()
#include <stdio.h>
#include <string.h> // For strlen
#include <ctype.h>  // For toupper

void toUpperCase(char *str) {
    // Step 1: Iterate through the string until the null terminator is found.
    for (int i = 0; str[i] != '\0'; i++) {
        // Step 2: Use toupper() to convert the character to uppercase.
        // toupper() returns the uppercase equivalent if it's a lowercase letter,
        // otherwise, it returns the character itself unchanged.
        str[i] = toupper((unsigned char)str[i]);
    }
}

int main() {
    char myString[] = "Hello, World! 123";

    printf("Original string: %s\n", myString);

    // Step 3: Call the toUpperCase function.
    toUpperCase(myString);

    printf("Uppercase string: %s\n", myString);

    return 0;
}