Question

I was provided this simple C++ [I think] program to investigate the maximum size of int that can be stored:

#include <limits.h>
#include <iostream>

void main ( int argc , char * argv[])

{

  cout << "INT_MAX      " << INT_MAX   << endl ;
  cout << "INT_MAX +1 = " << INT_MAX + 1  << endl ;
  cout << "INT_MAX -1 = " << INT_MAX - 1 << endl ;

  cout << "INT_MAX / INT_MAX        " << INT_MAX /INT_MAX << endl ;
  cout << "(INT_MAX +1) / INT_MAX   " << (INT_MAX +1) /INT_MAX << endl;
  cout << "(INT_MAX -1) / INT_MAX   " << (INT_MAX -1) /INT_MAX  <<endl;
  cout << "INT_MAX / (INT_MAX +1)   " << INT_MAX  /(INT_MAX+1)  <<endl;
  cout << "INT_MAX / (INT_MAX -1)   " << INT_MAX  /(INT_MAX -1)  <<endl;

}

I’m attempting to compile with:

gcc -o int_max int_max.cpp

But I get the following error:

int_max.cpp:4: error: '::main' must return 'int'
int_max.cpp: In function 'int main(int, char**)':
int_max.cpp:8: error: 'cout' was not declared in this scope
int_max.cpp:8: error: 'endl' was not declared in this scope
int_max.cpp:9: warning: integer overflow in expression
int_max.cpp:13: warning: integer overflow in expression
int_max.cpp:15: warning: integer overflow in expression

I tried adding a return 0 at the end of main but that didn’t help. Any idea what I’ve done wrong?

P.S It’s possible this is actually a C snippet but I seem to remember the lecturer saying it was C++.

Cheers

Answer 1

You are compiling C++ code with gcc in a file with .c extension?

// Use new C++ header files instead of their .h version.
#include <climits>
#include <iostream>

// cout and endl are declared in the std namespace.
using namespace std;

int main (int argc, char * argv[])    
{
  cout << "INT_MAX      " << INT_MAX   << endl ;
  cout << "INT_MAX +1 = " << INT_MAX + 1  << endl ;
  cout << "INT_MAX -1 = " << INT_MAX - 1 << endl ;

  cout << "INT_MAX / INT_MAX        " << INT_MAX /INT_MAX << endl ;
  cout << "(INT_MAX +1) / INT_MAX   " << (INT_MAX +1) /INT_MAX << endl;
  cout << "(INT_MAX -1) / INT_MAX   " << (INT_MAX -1) /INT_MAX  <<endl;
  cout << "INT_MAX / (INT_MAX +1)   " << INT_MAX  /(INT_MAX+1)  <<endl;
  cout << "INT_MAX / (INT_MAX -1)   " << INT_MAX  /(INT_MAX -1)  <<endl;

  return 0;
}

and use g++ to compile.