Encryption Program Problem

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Having trouble with this code that resembles a Caesar cipher (alphabet letter shift).

The task is to: (All lowercase letters)

1. Design a function, encrypt, that when applied to an unencrypted string un_str, transforms un_str to an encrypted string en_str using a right shift of length s to the letters of the alphabet with wraparound.
2. Design a function decrypt that when applied to an encrypted string en_str, transforms en_str to a decrypted string. The string en_str will have been encrypted with a cipher of length s.

Input: Shift length s, unencrypted string un_str, encrypted en_str
Output: String un_str and its encryption using function encrypt, String en_str and its decryption using function decrypt

Finished Program should be able to:

- Prompt for and get shift length x
- Prompt for and get unencrypted string un_str
- Encrypt un_str into en_str
- Prompt for and get encrypted string en_str
- Decrypt en_str into un_str

This is what I have so far, it’s obviously amateur’s work and I know there are SEVERAL errors as it is (though I’m not sure where ~). I’m trying to have it so that the program asks for a shift length, followed by offering a decrypt or encrypt option, followed by prompting for an entered string, and have the ability to perform those processes. Unfortunately I’m stuck. The string part, I really need help on. Thanks in advance

Code:

Title: 9.cpp

#include "9f.h"
#include <iostream>
#include <stdio.h>
#include <string>
using namespace std;

int main(void)
{
        char un_str[100];
        int shift;
        int crypt;

        std::cout << "Enter a desired shift length -> ";
        std::cin >> shift;

        std::cout << "Press 1 to encrypt or 0 to decrypt: ";
        std::cin >> crypt;
        while (getchar() != 'n');
        if (crypt == 1)
                encrypt(shift);
        else
        {
                decrypt(shift);
        }
               
        std::cout << "Enter a string -> ";
        std::cin.getline(un_str, 100);

        return 0;
}


Code:

Title: 9f.cpp

#include "9f.h"
#include <iostream>

void encrypt(int shift) // prototypes of functions used in the code
{
        char en_str;
        std::cout <<
        en_str = getchar();
        while(en_str != 'n')
        {
                if (ch == ' ')
                        putchar(en_str);
                else
                {
                        if(shift == 1)
                                putchar (en_str + shift);
                        else
                                putchar (en_str - shift);
                }
                en_str = getchar();
        }
        putchar(en_str);

        return 0;
}

void decrypt(int shift)
{
        shift = -1 * shift;
        encrypt(shift);
        return 0;
}


Code:

Title: 9f.h

void encrypt (int shift);
void decrypt (int shift);


See the original post:
Encryption Program Problem

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