Speed -- Functions vs "Main"

[jLNv0pDG]

I'm writing some basic programs that are hard on the CPU -- e.g. find all possible moves, prime numbers, etc. I know that you are encouraged to break main out into different functions but I was wondering if this has any negative impact on overall speed.

Basically, will Code 1 run (slightly) faster or at the same speed as Code 2?

//CODE 1.cpp
int main()
{
    cout << "hello";
    cout << "goodbye";
    return 0;
}

//CODE 2.cpp -- calling functions
int main()
{
    hello();
    bye();
    return 0;
}

void hello()
{
    cout << "hello";
}

void bye()
{
    cout << "goodbye";
}

[blackcoder41]

well yes, code 1 should run faster that very very very very very very tiny difference you cant notice.

[Bazzy]

if you inline the functions and the compiler takes the hint, the two programs would be the same.

[Duthomhas]

Function calls don't have any significant negative impact on performance except when you misuse them.

For example, if you are calculating Fibonacci numbers, using a recursive solution is a Bad Idea because you have to recalculate the (N-1)^th number for every N^th number you find, creating an exponential explosion in function calls == work done.

A well-designed algorithm, even one breaking the problem down into many sub-functions, is nearly always superior.

Hope this helps.