Question

I’m making a battleships game, so when I pass something such as “A10” into the coordinate function it needs to make column into letter and row into the number.

Coordinate(std::string coord = "A10")
    {
        char c = coord[0];
        col = c - 16;

        int r = atoi((coord.substr(1,2)).c_str());
        row = r-1;
    };

So in this example, passing A10 should make col = 0 (A=0,B=1,C=2) and row = 9.

The row equaling 9 seems to work but col equally 0 does not.

Answer 1

Are you trying to map the value of ‘A’ to zero? Remember that characters are single-byte integers,

char c = std::toupper( coord[0] );
if( c >= 'A' && c <= 'Z' )
{
    col = c - 'A';
}
else
{
    // TODO: Invalid/error?
}