Another Tutorial Question

Right-O.

I was presented with this code:

void main()
{
float a;
a=10/3;
printf("%f\n",a);
}

Then, later on in the text, they say this:

You do typecasting in C by placing the type name in parentheses and putting it in front of the value you want to change. Thus, in the above code, replacing the line a=10/3; with a=(float)10/3; produces 3.33333 as the result because 10 is converted to a floating point value before the division.

My question is, since variable a is already declared a float, why on God's green earth would you need to use a=(float)10/3. The text says you will get a different output this way. Why?

Lastly, please excuse the noobness of my questions, but in order for me to effectively learn something, I need to understand the why of things, and not simply the how.

RathMon

Math is done on the right side of the assignment first. So if you do not cast, it will do 10 / 3. Since 10 and 3 are both integers, you will get an integer result: 3. The 0.3333333 is truncated. Then, it assigns that to a float value, and so the result will be 3.000000.

You do not need to do (float) 10 / 3, but simply 10.0 / 3. 10.0 is read as a double, which can be assigned to a float. You can also do 10.0f / 3, which is taking a float value 10, and dividing by 3.