C++ double cant be equal to two int division

Question

I am a bit stuck with this problem:

int a = 5, b = 2;
double c = a / b;
cout << c;

This outputs:

2

Why ?

I can by pass this by using:

double aa = a,
bb = b;
c = aa / bb;

This outputs:

2.5

Help ! :(

Answer 1

You have to at least cast one of the ints to a double:

double c = a/(double)b;

Answer 2

In C++ language, any arithmetic operation between two integer values will return an int value. Said differently, the integer division is the Euclidian division. And only then that integer value is casted to a double.

If you want a double operation, you must force the division to operate on double values, either by casting one operand to double, or by multiplying it by 1.0 which is a double constant :

double c = 1.0 * a / b;

or

double c = static_cast<double>(a) / b;