Question

Disclaimer, new to programming, working my way through C++ Prime Plus 6th ed.

I’m working though listing 3.1.

#include <iostream> 
#include <climits>
int main()
{
    using namespace std;
    int n_int = INT_MAX;
    cout << "int is " << sizeof n_int << " bytes." << endl;

    return 0;

}

So I get, that creates a variable sets the max int value.

However, is there any reason why I should not and can’t go:

cout << "int is " << sizeof (INT_MAX) << " bytes." << endl;

As it gives the correct length. But when I try with (SHRT_MAX) it returns 4 bytes, when I’d hoped it would return 2.

Again with (LLONG_MAX) it returns correctly 8 bytes, however (LONG_MAX) incorrectly returns 8.

Any clarification would be great.

Answer 1

The values defined in <climits> are macros that expand to integer literals. The type of an integer literal is the smallest integer type that can hold the value, but no smaller than int.

So INT_MAX will have type int, and so sizeof INT_MAX is the same as sizeof (int). However, SHRT_MAX will also have type int, and so sizeof SHRT_MAX will not necessarily equal sizeof (short).