How to make each letter in a string not case sensitive

Question

I'm learning C++ right now, but I can't seem to find out how to make an input be accepted whether or not there are any capitals anywhere. For example, if someone input "sAndwiCh" in a case in a switch statement desiring "sandwich," how could I perform the following action by making the program allow the input to be any case of every letter? Thank you.

Answer 1

Use the toupper() and/or the tolower() functions of the ctype.h header file. So, to make your comparisons:

char input[3] = {'A', 'b', 'C'};
unsigned int index = 0U;
unsigned int outputVal = 0U;

while(index < 3) {
    switch(tolower(input[index])) {
        case 'a': 
            outputVal += 1;
            break;
        case 'b':
            outputVal += 2;
            break;
        case 'c':
            outputVal += 3;
            break;
    }
    ++index;
}

At the end of this, outputVal should have a value of 6.