Permgood

/*      Introduction to program:
        Program - permgood.c.
        Example of how to permute three numbers.
        Francis O'Donovan 2-2-98. */

/* Files to be included. */

#include <stdio.h>

/* ********************************************** */

/* Function: main(). */

main()
{
/* Declare functions. */

void Permute();

/* Initialize variables. */

int x, y, z; /* The three numbers to be used. */

/* Print introduction. */

        printf( "Program: permgood.c.\n" );
        printf( "Example of how to permute three numbers.\n" );
        printf( "Francis O'Donovan 2-2-98.\n\n" );

/* Get user to input numbers. */

        printf( "Please type in three numbers, x, y, and z:\n" );
        scanf( "%d", &x );
        scanf( "%d", &y );
        scanf( "%d", &z );

        /* Call Permute(). */

Permute( &x, &y, &z );

/* Output the three numbers. */

printf( "x = %d, y = %d, z = %d.\n", x, y, z );
}

/* ************************************************ */

/*      Function: Permute().
        Purpose: Permutes three integers.
        Arguements: Three pointers to ints.
        Returns: void.
*/

void Permute( x, y, z)
int *x, *y, *z;
{
/* Initialise variables. */

int temp; /* temporary holder. */

/* Attempt to permute the numbers. */

        temp = *x;
        *x = *y;
        *y = *z;
        *z = temp;
}

/* Comment:
        This program will permute the three numbers, because it passes the
        addresses of the variables in main() to the function Permute,
        so Permute can change them directly.
*/

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