/*************************************
** File: structs.c
** Author: D. Frey
** Date: 1/24/00
** Section: 0101
** E-Mail: frey@cs.umbc.edu
** Modified by: Sue Evans
** Date: 2/29/04
** Modified to meet current 201 standards
**
** This file demonstrates the basics of
** nested structures, the use of one structure
** within the definition of another.
***************************************/
#include <stdio.h>
/* structure definitions */
/* a point with x- & y-coodinates */
struct point
{
int x;
int y;
};
/* a line defined by 2 points */
struct line
{
struct point startPoint;
struct point endPoint;
};
int main ( )
{
struct line aLine;
struct point point1, point2;
struct point midPoint;
/* initialize point1 */
point1.x = point1.y = 0;
/* initialize point2 */
point2.x = 10;
point2.y = 6;
/* print the points */
printf ("\n");
printf ("Point1: (%d, %d)\n", point1.x, point1.y);
printf ("Point2: (%d, %d)\n\n", point2.x, point2.y);
/* calc and print midpoint between point1 & point2 */
midPoint.x = (point1.x + point2.x) / 2;
midPoint.y = (point1.y + point2.y) / 2;
printf ("The midpoint is (%d, %d)\n\n", midPoint.x,
midPoint.y);
/* now think of the line as a structure */
/* init the line by assigning the points */
aLine.startPoint = point1;
aLine.endPoint = point2;
/* change the x-coordinate of the endpoint */
aLine.endPoint.x = 8;
/* print the line */
printf ("The line's startpoint: (%d, %d)\n",
aLine.startPoint.x, aLine.startPoint.y);
printf ("The line's endpoint: (%d, %d)\n",
aLine.endPoint.x, aLine.endPoint.y);
return 0;
}
The Output
linux1[102] % a.out
Point1: (0, 0)
Point2: (10, 6)
The midpoint is (5, 3)
The line's startpoint: (0, 0)
The line's endpoint: (8, 6)