C++ int float casting

Question

Why is m always = 0? The x and y members of someClass are integers.

float getSlope(someClass a, someClass b)
{           
    float m = (a.y - b.y) / (a.x -         


        

Answer 1

Because (a.y - b.y) is probably less then (a.x - b.x) and in your code the casting is done after the divide operation so the result is an integer so 0.

You should cast to float before the / operation

Answer 2

if (a.y - b.y) is less than (a.x - b.x), m is always zero.

so cast it like this.

float m = ((float)(a.y - b.y)) / ((float)(a.x - b.x));