The C programming language graphics support allows creating polygon shapes with N points. Each of these N points must be a pair of coordinates. In this article, you will write a program to draw a polygon shape in C language.
Problem Definition
We wish to create a polygon shape with 4 points. Each of the points will be represented using a pair (x, y) where x is x-coordinate and y is y-coordinate in the x-axis and y-axis respectively.
The program must go through the following steps to create a polygon:
- Declare all variables including graphics variables and polygon array.
- Initialize all variables.
- Initialize the graph while the path is set to the graphics driver.
- Assign values to polygon array in pairs.
- Use drawpoly( ) function to draw the polygon shape.
- Close the graph.
Program Code – Polygon using drawpoly( )
/* C Program to draw a Polygon in C language */
#include <graphics.h>
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
int main()
{
/* Declaring a variable */
int gdriver, gmode;
/* Polygon array to define points on the polygon shape */
int poly[10];
/* Initialize the variables */
gdriver = DETECT;
/* Initialize the graph and set path to BGI files */
initgraph(&gdriver, &gmode, "D:\\TURBOC3\\BGI");
/* Polygon Points in Pairs */
poly[0] = 20; /* 1st vertex */
poly[1] = 100;
poly[2] = 120;
poly[3] = 140; /* 2nd vertex */
poly[4] = 240;
poly[5] = 260; /* 3rd vertex */
poly[6] = 120;
poly[7] = 320; /* 4th vertex */
poly[8] = poly[0];
poly[9] = poly[1]; /* The polygon does not
close automatically, so we close it */
/* Draw the Polygon */
drawpoly(5, poly);
getch();
/* Close the graph */
closegraph();
return 0;
}Output
