ceasar cipher cpp

// program to implement ceasar cipher encryption

#include <iostream>
#include <vector>
#include <algorithm>
#include <fstream>
#include <sstream>

using namespace std;

// function that takes original message and shift value as input and returns encrypted message string as output
string encrypt(string original_msg, int shift_value){

    string allChars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ !\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";
    int all_chars_length = allChars.length();


    string encrypted_msg = "";

    for(int i=0; i< original_msg.length(); i++){
        char letter = original_msg[i];
        int position = allChars.find(letter);
        if(position >= 0) {
            position += shift_value;
            position %= all_chars_length;
            char e_letter = allChars[position];
            encrypted_msg += e_letter;

        }else{
            encrypted_msg += letter;
        }
    }


    return encrypted_msg;
}

// function the takes path of the file to be encrypted and then stores the encrypted file on desktop
static void encrypt_file(int shift_value){
    ifstream input_file;
    string file_name, data;
    cout<<"Enter File name : ";
    cin>>file_name;
    try {
        input_file.open(file_name);
        stringstream ss;
        ss << input_file.rdbuf();
        data = ss.str();
        cout<<"File read successufully!!"<<endl;
    } catch(exception e){
        cout<<e.what();
    }
    string encrypted_data = encrypt(data, shift_value);
    cout<<"File data encrypted successfully!!"<<endl;
    ofstream output_file;
    try {
        output_file.open("C:\\Users\\MOHIT\\Desktop\\ss.txt");
        output_file << encrypted_data;
        output_file.close();
        cout<<"Encrypted file stored on Desktop!!"<<endl;
    }catch(exception ee){
        cout<<ee.what();
    }


}

int main()
{
    //cout << encrypt("My name is mohit, hello", 3) << endl;
    cout<<"Program to implement Ceasar Cipher"<<endl;
    cout<<"Enter shift value for Encryption : ";
    int shift_value;
    cin>>shift_value;
    encrypt_file(shift_value);
}

/*
Output for encrypting a file


Enter File name :F:/python_3.4/sample.txt
Enter File name : F:/python_3.4/sample.txt
File read successufully!!
File data encrypted successfully!!
Encrypted file stored on Desktop!!


 */