Captcha program in C with Source code

This program generates captcha, a captcha is a random code generated using some algorithm. We will use random function in our code. These are used in typing tutors and in website to check whether a human is operating on a website.

C programming code

#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;
   }
}

Output of program:

Cool Hack,To print Series of numbers without LOOP

Hello friends today i am posting this new code which is very interesting .C program to print first n natural numbers without using any loop(do while, for or while). In the first program we will use recursion to achieve the desired output and in the second we use goto statement i.e. without creating any function other than main

C programming code using recursion

#include <stdio.h>
 
void print(int);
 
int main()
{
  int n;
 
  scanf("%d", &n);
 
  print(n);
 
  return 0;
}
 
void print(int n)
{
  static int c = 1;
 
  if (c == n+1)
    return;
 
  printf("%d\n", c);
  c++;
  print(n);
}

OUTPUT OF ABOVE CODE: