Thread: why square functions returns double instead of integer?

Originally Posted by V8cTor

yeah maybe but according to me, the latter also works fine.

Of course it does, but what if you want to square pi? Or e? what about some other non-whole number? What are you going to do then?

Originally Posted by V8cTor

why square functions returns double instead of integer?

I think that your question makes an incorrect assumption to begin with: there is no function named square in the C++ standard library. There are examples of functions that coincidentally are named square, e.g.,

Originally Posted by C++11 Clause 7.1.5 Paragraph 1 (part)

Code:

constexpr int square(int x) {  // OK: definition
    return x * x;
}

And lo and behold, the example is of your latter variety, so in fact "functions for finding square" are written like that! Yet this is just an example. You can define your function named square as you see fit. You can even overload:

Code:

double square(double x) {
    return x * x;
}

int square(int x) {
    return x * x;
}

Or perhaps define a function template:

Code:

template<typename T>
T square(T x) {
    return x * x;
}