Changing Cases in a String

ASCII values and it's importance in changing cases in a string.

Common ASCII Codes:

• A = 65

• Z = 90

• a = 97

• z = 122

The Logic:

To covert from uppercase to lowercase, add 32 to the uppercase character.

To convert from lowercase to uppercase, subtract 32 from the lowercase character.

C Function:

void toUpper(char A[]) {
    
    for (int i = 0; A[i] != '\0'; i++) {
        A[i] = A[i] - 32;
    }
    
}

void toLower(char A[]) {

    for (int i = 0; A[i] != '\0'; i++) {
        A[i] = A[i] + 32;
    }    

}

void toggleCase(char A[]) {

    for (int i = 0; A[i] != '\0'; i++) {
        if (A[i] >= 'A' && A[i] <= 'Z') {
            A[i] = A[i] + 32;
        } else if (A[i] >= 'a' && A[i] <= 'z') {
            A[i] = A[i] - 32;
        }
    }

}

Contributed by Nitin Ranganath