Answer to Question #196471 in C++ for Faiz

Question

A shift cipher (a.k.a. Caesar’s cipher) is a simple substitution cipher in which each letter in the plaintext is replaced with another letter that is located a certain number, n, positions away in the alphabet. The value of n can be positive or negative. For positive values, replace letters with letters located n places on its right (i.e. ‘shifted’ by n positions to the right). For negative values, replace letters with letters located n places on its left. If it reaches the end/start of the alphabets, wrap around to the start/end. For example: If n = -3, each letter in the plaintext is replaced with a letter 3 positions before that letter in the alphabet list.

Answer 1

#include <iostream>
using namespace std;
 


string encrypt(string text, int s)
{
    string result = "";
 
   
    for (int i=0;i<text.length();i++)
    {
        
        if (isupper(text[i]))
            result += char(int(text[i]+s-65)%26 +65);
 
    
    else
        result += char(int(text[i]+s-97)%26 +97);
    }
 
    
    return result;
}
 


int main()
{
    string text="DEFENDATONECE";
    int n = 4;
    cout << "Text : " << text;
    cout << "\nShift: " << n;
    cout << "\nCipher: " << encrypt(text, n);
    return 0;
}