#include "prog4.h"

/* This program illustrates how to get two values back from a function.
 *
 * Since functions can only return a single value, we must either get
 * the values back via parameters, or create a structure that contains
 * the two values.  This program illustrates passing values back in
 * a structure.
 *
 * Note that C implements "pass by value" (known more informally as
 * pass by copy).  That means that a copy of each value is passed.  If
 * the function changes the parameter, it is only changing its own copy.
 * To simulate "pass-by-reference", we must pass the ADDRESS of the
 * variable whose value we wish to change.  The address is passed by
 * value, but that's OK because we don't want to change the address,
 * we want to change the value AT that address.
 */

int main(int argc, char *argv[])
{
	int     i;          /* loop index variable */
        TwoNums aStruct;    /* a structure containing 2 ints */

        /* Set num1 and num2 to start with. */
        aStruct.num1 = 111;
        aStruct.num2 = 222;

	/* Print num1 and num2. */
	printf("\n\tIn main: The initial numbers are %d and %d.\n\n\n",
                aStruct.num1, aStruct.num2);

	/* Get two numbers. */
	fill2Nums(&aStruct);    /* Pass ADDRESS of aStruct. */

	/* Print num1 and num2. */
	printf("\n\tIn main: The user typed in %d and %d.\n\n\n", 
                aStruct.num1, aStruct.num2);

}