Example: Case Conversion using Manual ASCII in C

// Case Conversion using Manual ASCII
#include <stdio.h>

// Function to convert string to lowercase using ASCII
void toLowerCase_ascii(char *str) {
    for (int i = 0; str[i] != '\0'; i++) {
        // Check if the character is an uppercase letter (A-Z)
        if (str[i] >= 'A' && str[i] <= 'Z') {
            str[i] = str[i] + 32; // Add 32 to convert to lowercase
        }
    }
}

// Function to convert string to uppercase using ASCII
void toUpperCase_ascii(char *str) {
    for (int i = 0; str[i] != '\0'; i++) {
        // Check if the character is a lowercase letter (a-z)
        if (str[i] >= 'a' && str[i] <= 'z') {
            str[i] = str[i] - 32; // Subtract 32 to convert to uppercase
        }
    }
}

int main() {
    // Step 1: Define strings for conversion
    char myString1[] = "Hello Manual World!";
    char myString2[] = "cOdInG wItH aScIi.";

    // Step 2: Convert to lowercase using ASCII and print
    printf("Original: \"%s\"\n", myString1);
    toLowerCase_ascii(myString1);
    printf("Lowercase (ASCII): \"%s\"\n\n", myString1);

    // Step 3: Convert to uppercase using ASCII and print
    printf("Original: \"%s\"\n", myString2);
    toUpperCase_ascii(myString2);
    printf("Uppercase (ASCII): \"%s\"\n\n", myString2);

    return 0;
}