Question

Program:

   int main( )
    {
    printf("%d",printf("%d %d",5,5)&printf("%d %d",7,7));
    return 0;
    }

Output:

5 57 73

I am new to C, I could guess where the 5 57 7 came from, but no idea where the 3 came from. Can someone explain the output?

Answer 1

If you apply binary AND to 3 and 3 (which are the return values of both nested printf calls) you get 3 as result.

Note that the code actually contains undefined behaviour, since the order of the nested calls isn’t defined.