// Ex5_02.cpp
  // A futile attempt to modify caller arguments
  include <iostream>
  using std::cout;
  using std::endl;
  
  int incr10(int num);           // Function prototype
  
  int main(void)
  {
     int num = 3;
  
     cout << endl
             << "incr10(num) = " << incr10(num)
             << endl
             << "num = " << num;
  
     cout << endl;
     return 0;
  }
  
  // Function to increment a variable by 10
  int incr10(int num)            // Using the same name might help...
  {
     num += 10;                  // Increment the caller argument – hopefully
  
     return num;                 // Return the incremented value
  }