sizeof(array) returns different values in main() and user defined functions

[lancelot]

Hello, everyone. I found sizeof(array) only works correctly in main() function.
Could you please tell me why?

-------------------------------------------------
#include <iostream>
using namespace std;

int f(const int array[]){
cout << sizeof(array) << endl;
//cout << array[index] << endl; //1
}

int main(){
int array[5] = {3,4,9,1,5};
cout << sizeof(array) << endl;
f(array);
return 0;
}

The output is:
20
4
------------------------------------------------
but if I print the whole array in f() (remove comment at 1),
the array content can be still printed out.

Can anyone explain the reason behind it?

Thank you very much.

[jsmith]

Answered in general c++ forum.

[lancelot]

Thanks for telling me. :-)