Base Conversion Program any base to any base

With this program you can convert the base of a real number. This program works on any base.

  /*PROGRAM TO CONVERT BASE OF A NUMBER (DECIMAL POINT ALSO)*/
  /*THIS PROGRAM CONTAINS VALIDATION CHECKS ALSO*/
  /*DESIGNED AND OWNED BY "KALYAN" */
  /*TOTAL NO OF LINES-----158*/

#include<stdio.h>
#include<math.h>
#include<conio.h>
#include<string.h>
#include<ctype.h>
float decimal;
main()
 {
  char ch,s[33],s1[33],s2[33],*p,dot;
  int m,n,a1[33],a2[33],b,i,k,l;
  float f=0,deci=0,z=0;
  clrscr();
  printf("Enter Base of number you want:(2,8,10,16)");
  scanf("%d",&b);
   if(b==2||b==8||b==10||b==16)
   {
   printf("Enter Number :");
  scanf("%s",&s);
  l=strlen(s);
  }
   else
    {
     printf("INVALID BASE.......");
     main();
    }
 /*validation check for number*/
  for(i=0;i<=l;i++)
   {
    switch(b)
      {
    case 2 :
      {
       if(strchr("01.",s[i])==NULL)
        {
         printf("
Invalid number.... Again enter the number:");
         scanf("%s",&s);
        }
       break;
      }
      case 8:
      {
       if(strchr("01234567.",s[i])==NULL)
        {
         printf("
Invalid number.... Again enter the number:");
         scanf("%s",&s);
        }
       break;
      }
     case 10 :
          {
       if(strchr("0123456789.",s[i])==NULL)
        {
         printf("
Invalid number.... Again enter the number:");
         scanf("%s",&s);
        }
       break;
      }
     case 16 :
          {
       if(strchr("0123456789ABCDEF.",s[i])==NULL)
        {
         printf("
Invalid number.... Again enter the number:");
         scanf("%s",&s);
        }
       break;
      }
      }
   }
  p=strchr(s,'.');
  k=p-s;
     for(i=0;i<=l-1;i++)
      {
       if(i>k)
    s2[i-(k+1)]=s[i];
       else
    s1[i]=s[i];
      }
  s2[i-k-1]='