// --- Example x12: Functions. Arguments by value
/*
    Demonstrates that a function has its own local
	variables. Arguments passed to it by value
	are NOT shared variables. Only the value
	of the variable is received at run time.
     -----------------------------------------------
*/

#include <iostream.h>
int double_value ( int i )
{
 /*   This function uses type conversion to add its arguments
    and return the sum. It illustrates the locality of the
    variables in its argument list.
  */

	cout << "\n ---------------------------- ";
	cout << "\n  Beginning function \"double_value( int i )\"";
	cout << "\n ---------------------------- ";

	cout << "\n i = " << i  ;

        cout << "\n Doubling...\n";
        i += i;
	   
	cout << "\n Now i = " << i  ;
 
	cout << "\n ---------------------------- ";
        cout << "\n End function \"double_value()\"";
	cout << "\n ----------------------------\n ";
        return i;
}

int main(void) 
{
   int   imain = 5; 

	cout << "\n ----------------------------\n ";
	cout <<    " Beginning function \"main()\"";
	cout << "\n ---------------------------- ";

	cout << "\n imain = " << imain ;

//      cout << "\n ----------------------------\n "
	cout << " \n Calling function: double_value( imain )";
//       cout << "\n ---------------------------- ";


 	int jmain = double_value( imain );
	   
	cout << " ----------------------------\n "
	     <<    " Back in function \"main()\"";
	cout << "\n ---------------------------- ";

	cout << "\n returned value (2*imain)  = " << jmain;
	cout << "\n Now imain = " << imain ;
 
        cout << "\n Note: the value of imain is "
	     << "\n UNCHANGED by the call to \"double_value().\" \n ";

        return 0;
}