Captcha Program

/*
Write a program in C for Captcha Generation
*/
 
#include<stdlib.h>
#include<dos.h>
#include<graphics.h>

main()
{
int i = 0, key, num, midx, gd = DETECT, gm;
char a[10];

initgraph(&gd,&gm,"C:\\TC\\BGI");

midx = getmaxx()/2;

settextstyle(SCRIPT_FONT,HORIZ_DIR,5);
 
settextjustify(CENTER_TEXT,CENTER_TEXT);
 
setcolor(GREEN);
 
outtextxy(midx,20,"CAPTCHA");
 
settextstyle(SCRIPT_FONT,HORIZ_DIR,2);
 
outtextxy(midx,125,"Press any key to change the generated random code \"captcha\"");
 
outtextxy(midx,150,"Press escape key to exit...");

setcolor(WHITE);
 
setviewport(100,200,600,400,1);
 
setcolor(RED);
 
randomize();

while(1)
{
 
while(i<6)
{
 
num = random(3);

if ( num == 0 )
 
a[i] = 65 + random(26); /* 65 is the ascii value of A */
 
else if ( num == 1)
 
a[i] = 97 + random(26); /* 97 is the ascii value of a */
 
else
 
a[i] = 48 + random(10); /* 48 is the ascii value of 0 */
 
i++;
}
 
a[i] = '\0';
 
outtextxy(210,100,a);
 
key = getch();

if( key == 27 ) /* escape key*/
 
exit(0);
 
clearviewport();
 
i = 0;
}
}