(-) Symbol Used in Convert Method

Question

I was going through some C# code and came upon this line:

Matrix[i, j] = Convert.ToInt32(grab[i, j] - '0');

What exactly does the ( - ) do??

What would be another way to write this if there is one?

Answer 1

The - (minus) does exactly what it always does - subtracting. What happens here is subtracting the character code of zero '0' from the character at [i,j]. This converts a digit character to an integer value of the corresponding digit. For example, if you calculate

char digitChar = '7';
int digitVal = digitChar - '0';

the value of digitVal is seven.