Sanjay Kumar Chakravarti

//IMPLEMENTATION OF AUTO KEY IN C++

#include<iostream.h>

#include<conio.h>

#include<string.h>

void main(){

clrscr();

char *plain,*key,alp[]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};

int plen,klen,i,count=0,ct[50];

cout<<"\n\n\t\t*******This Program Done By:Sanjay Kumar Chakravarti**********";

cout<<"\nEnter Text:";

cin>>plain;

cout<<"\nEnter Key:";

cin>>key;

plen=strlen(plain);

klen=strlen(key);

if(klen<plen){

for(i=klen;i<plen;i++){

key[i]=plain[count];

count++;

}

}

cout<<"\nNow Key will be:";

for(i=0;i<plen;i++){

cout<<key[i];

}

int j,k;

for(i=0;i<plen;i++){

for(j=0;j<26;j++){

if(plain[i]==alp[j]){

ct[i]=j;

for(k=0;k<26;k++){

if(key[i]==alp[k]){

ct[i]+=k;

}

}

}

}

}

char *cih;

cout<<"\nCipher Text will be:";

for(i=0;i<plen;i++){

ct[i]=ct[i]% 26;

cih[i]=alp[ct[i]];

//cout<<ct[i]<<" ";

cout<<alp[ct[i]];

}

cout<<"\n\t\tDecryption:";

int ct1[50];

for(i=0;i<plen;i++){

for(j=0;j<26;j++){

if(cih[i]==alp[j]){

ct1[i]=j;

for(k=0;k<26;k++){

if(key[i]==alp[k]){

ct1[i]-=k;

}

}

}

}

}

cout<<"\nOriginal Plain Text will be:";

for(i=0;i<plen;i++){

ct1[i]=ct1[i]% 26;

if(ct1[i]<0){

ct1[i]=ct1[i]+26;

}

//cih[i]=alp[ct1[i]];

//cout<<ct[i]<<" ";

cout<<alp[ct1[i]];

}

getch();

}