Simple Encryption...

[3872Nwbp]

Just to try to expand my skills, how basic they might be, I decided to try basic encryption/decryption. This is my start at encryption... And it IS basic. Haha.

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
	string given, encrypted;
	int length, key;
	
        // Input
	cout << "Please type what is to be encrypted:" << endl;
	getline(cin, given);

	length = given.length();    // Get length of string

	cout << endl << "Please enter the encryption key: ";
	cin >> key;        // number by which characters will be changed

	for(int a = 0; a < length; a++)         // the main loop
		encrypted[a] = given[a] + key;

         // Output
	cout << endl << "Your given text is: " << endl << encrypted << endl << endl;
	
	system("pause");
	return 0;
}

When I run this, I get an error message "string subscript out of range". I've tried things like converting the strings to char arrays, which have a whole other problem themselves, and by now, a few hours on google. Including staring at my screen and going through each line multiple times. I'm at a huge loss. Any help is well appreciated, including anything about my coding not really related to this problem.

[Moschops]

The error message indicates that you are trying to write into encrypted to elements that do not exist. You can ensure the elements exist by setting

getline(cin, given);
encrypted = given;

right after you read into given; that will guarantee that encrypted is large enough to take all the new letters.


Alternatively

length = given.length();    // Get length of string
encrypted.resize(length);

[tejashs]

line 23 encrypted[a] = given[a] + key;
you should know that encrypted[a] can hold data only from 0 to 255

[tejashs]

you should know that encrypted[a] can contain data only from 0 - 255 see line 23
encrypted[a] = given[a] + key;

[3872Nwbp]

@Moschops Thank you very much, that makes a lot of sense.

@tejashs And yes I do know that, thanks for the reminder.

Works fine now! Thanks guys!