How to convert char to float?

Question

I am trying to convert two char numbers into float, but I am not getting the correct result.

char firstnumber = '1';
char secondnumber = '2';
float sum  ;

sum =  ((firstnumber - '0') /(secondnumber - '0'));
cout << sum;

The output is always 0 , rather than 0.5 , please enlighten me.

Answer 1

You're doing integer division, which truncates the result. You need to add a typecast to get at least one of the / operands to be a floating point number.

sum = (float)(firstnumber - '0') / (secondnumber - '0');

Answer 2

When you divide two integers, you get integer division. You want:

sum =  (firstnumber - '0');
sum /= (secondnumber - '0');

(Or some other way of accomplishing the same thing.)