CODEWITHSUNDEEP
c++
user7493939
user7493939

Reputation:

Random number is returned

The following code : 

#include <iostream>
using namespace std;
int test()
{
    cout<<"question \n";
    return 0;
}
int main(){
    cout<<test;
}

Output: question 1

The following code gives 1 everytime I run but I am expecting the output to be 0.

Whereas when I replace the test by test() then I get the expected output. Not sure why is this happening. Please suggest and comment if any rule behind it.

Upvotes: 0

Views: 64

Answers (2)

MSD
MSD

Reputation: 1407

std::cout << test;

Outputs 1 because test is a function pointer, it will be converted to bool with std::cout.

Upvotes: 0

Joseph Sible-Reinstate Monica
Joseph Sible-Reinstate Monica

Reputation: 48572

C++ always requires you to use parentheses to call functions. If you omit them, it thinks you want to know the address of the function instead of calling it. The address is then considered to be a (truthy) boolean and gets output as 1. This warning (from gcc -Wall) explains it well:

x.cpp: In function ‘int main()’:
x.cpp:9:11: warning: the address of ‘int test()’ will always evaluate as ‘true’ [-Waddress]
     cout<<test;
           ^

Upvotes: 2

Related Questions