#include<iostream.h>
#include<conio.h>
#include<string.h>
#include<stdio.h>
#include<stdlib.h>
void main()
{ clrscr();
char string[30],string1[30],opt;
int ascii,n,i;
cout<<\"\\n\\tCODED BY AYESEYEF\";
cout<<\"\\n\\tSelect the operation you would like to perform\";
cout<<\"\\n\\n\\t\\tOperation List\\n\";
cout<<\"\\n\\tE - ENCRYPTION AND D - DECRYPTION\\n\\n\\t\\t\";
cin>>opt;
if(opt==\'e\')
{	opt=\'E\';
}
else if(opt==\'d\')
{	opt=\'D\';
}
switch(opt)
{	case\'E\': cout<<\"\\tEnter the string to be encrypted by rot13 algorithm\\n\\t\";
gets(string1);
n=strlen(string1);
for(i=0;i<n;i++)
{	ascii=string1[i];
if((ascii>=48)&&(ascii<=57))
{	cout<<\"\\n\\tThe string cannot be encrypted\\n\";
cout<<\"\\tPress any key to exit\";
getch();
exit(0);
}
}
for(i=0;i<n;i++)
{ ascii=string1[i];
if((ascii>=65)&&(ascii<=77))
{	string[i]=ascii+13;
}
else if((ascii>77)&&(ascii<=90))
{	string[i]=ascii-13;
}
else if((ascii>=97)&&(ascii<=109))
{	string[i]=ascii+13;
}
else if((ascii>109)&&(ascii<=122))
{	string[i]=ascii-13;
}
else if(ascii==32)
{	string[i]=ascii;
}
else
{	cout<<\"\\n\\tSpecial characters are not encryptable\";
cout<<\"\\nPress any key to exit\";
getch();
exit(0);
}
}
cout<<\"\\n\\tThe encrypted string for the text:\";
puts(string1);
cout<<\"\\tis\\t\";
break;
 
case\'D\': cout<<\"\\n\\tEnter the Rot13 encrypted string\\n\\t\";
gets(string1);
n=strlen(string1);
for(i=0;i<n;i++)
{	ascii=string1[i];
if((ascii>=48)&&(ascii<=57))
{	cout<<\"\\n\\tThe string cannot be decrypted\\n\";
cout<<\"\\tPress any key to exit\";
getch();
exit(0);
}
}
for(i=0;i<n;i++)
{ ascii=string1[i];
if((ascii>=65)&&(ascii<=77))
{	string[i]=ascii+13;
}
else if((ascii>77)&&(ascii<=90))
{	string[i]=ascii-13;
}
else if((ascii>=97)&&(ascii<=109))
{	string[i]=ascii+13;
}
else if((ascii>109)&&(ascii<=122))
{	string[i]=ascii-13;
}
else if(ascii==32)
{	string[i]=ascii;
}
else
{	cout<<\"\\n\\tSpecial characters are not decryptable\\n\";
cout<<\"\\n\\tPress any key to exit\";
getch();
exit(0);
}
}
cout<<\"\\n\\tThe decrypted plain text for the string:\";
puts(string);
cout<<\"\\tis\\t\";
break;
 
default: cout<<\"\\n\\tWrong option\";
cout<<\"\\n\\tPress any key to exit\";
getch();
exit(0);
}
puts(string);
getch();
}