C code for character stuffing

#include<stdio.h>

#include<conio.h>

void ins(char,int);

void del(int,int);

char fr[50];

main()

{

 int i,cnt=0,ch;

 clrscr();

 printf("Enter the frame:\t");

 gets(fr);

 /*Charecter Stuffing*/

            ins('s',0);

            ins('e',5);

            //printf("%s",fr);

            for(i=0;i<strlen(fr);i++)

            {

             if(fr[i]=='d'&&fr[i+1]=='l'&&fr[i+2]=='e'&&i!=3&&i!=strlen(fr)-3)

             {

              ins('m',i+3);i+=6;

             }

            }

            printf("\n\nStuffed bit is \t%s\t",fr);getch();

            /*Destuffing*/

            cnt=0;

            del(0,6);

            del(strlen(fr)-6,6);

            for(i=0;i<strlen(fr);i++)

            {

             if(fr[i]=='d'&&fr[i+1]=='l'&&fr[i+2]=='e')

             {

             cnt+=1;

             if(cnt==1)

             {         del(i,3);}

             }else

             {cnt=0;}

            }

            printf("\n\nDestuffed bit is \t%s",fr);getch();

            return 0;

 }

void ins(char in,int p)

{

 char dup[50];

 int i;

 strcpy(dup,fr);

            if(in=='s')

            {

             fr[p]='s';

             fr[p+1]='t';

             fr[p+2]='x';

             fr[p+3]='d';

             fr[p+4]='l';

             fr[p+5]='e';

            for(i=p+6;i<strlen(fr)+6;i++)

            {

             fr[i]=dup[i-6];

            }

            }

            if(in=='e')

            {

             strcat(fr,"etxdle");return;

            }

            if(in=='m')

            {

             fr[p]='d';

             fr[p+1]='l';

             fr[p+2]='e';

             for(i=p+3;i<strlen(fr)+3;i++)

             {

             fr[i]=dup[i-3];

             }

            }

            }

void del(int q,int n)

{

 int i;

            for(i=q;i<strlen(fr);i++)

            {

             fr[i]=fr[i+n];

            }

}

OUTPUT: