Exercise 6a C program to delete a number of charecters

/* Write a C program that uses functions to perform the following operation:To delete n Characters from a given position in a given string.
*/
#include<stdio.h>
#include<conio.h>
#include<string.h>
main()
{
 char a[100], b[100];
 int i,j,n;
 int p;
 clrscr();
 printf("\n Enter the String of Charecters");
 gets(a);
 Printf("\n Enter the position from where the string has to be deleted");
 scanf("%d",&p);
 printf("\n Enter the no. of charecters you want to delete");
 scanf("%d",&n);
 r=strlen(a);
 if((n+p)>r)
  {
     printf("\n End of String reached");
     printf("\n Please enter a valid no. of charecters..");
  }
  for(i=0;i<r;i++);
  {
    b[i]=a[i];
  }
  for(i=p;i<r;i++)
  {
    b[i]='\0';
  }
   /*             or
   int c[100]
   for(i=0;i<p-1;i++)
    c[i]=b[i];

  */
  printf("\n The String after deleting the substring is");
  printf("%s",b);
   /*printf("%s",c);*/
   getch();
}