CODEWITHSUNDEEP
c++stringencryption
high 0n C
high 0n C

Reputation: 57

Why am i getting memory errors?

Iam getting this memory error when i run this c++ program and execute its functions any ideas why

Unhandled exception at 0x769DC41F in TESTER 12345.exe: Microsoft C++ exception: std::invalid_argument at memory location 0x0042F558.

iam running this on Visual studio 2013.

#include <iostream>
#include <string>
#include <algorithm>
#include <iomanip>
#include <cmath>

using namespace std;

string encrypt(string, int);
string decrypt(string source, int key);
int main(int argc, char *argv[])
{
    string Source;
    string userInput;
    string keyString;

    int Key;
    int locationSpace = 0;
    int locationOfFirstKeyIndex = 0;

    int choice;

    /*locationSpace = userInput.find(" ");

    keyString = userInput.substr(locationOfFirstKeyIndex, locationSpace);
    Source = userInput.substr(locationSpace + 1);

    Key = stoi(keyString);*/

    cout << "To encode a message type 1, to decode a message type 2: ";
    cin >> choice;

    if (choice == 1)
    {
        cin.ignore();
        cout << "Enter a message to decode: ";
        getline(cin, Source);
        locationSpace = userInput.find(" ");

        keyString = userInput.substr(locationOfFirstKeyIndex, locationSpace);
        Key = stoi(keyString);
        Source = userInput.substr(locationSpace + 1);

        encrypt(Source, Key);
        cout << "Encrypted: " << encrypt(Source, Key) << endl;
    }
    else if (choice == 2)
    {
        cin.ignore();
        cout << "Enter the message To decode: ";
        getline(cin, userInput);
        locationSpace = userInput.find(" ");

        keyString = userInput.substr(locationOfFirstKeyIndex, locationSpace);
        Key = stoi(keyString);
        Source = userInput.substr(locationSpace + 1);


        decrypt(Source, Key);
        cout << "Decrypted: " << decrypt(Source, Key) << endl;
    }
    else
    {

        cout << "Invalid Input";
    }

    system("pause");
}

string encrypt(string source, int key)
{
    string Crypted = source;

    for (int Current = 0; Current < source.length(); Current++)
        Crypted[Current] = ((Crypted[Current] + key) - 32) % 95 + 32;
    return Crypted;
}

string decrypt(string source, int key)
{
    string Crypted = source;

    for (int Current = 0; Current < source.length(); Current++)
        Crypted[Current] = ((Crypted[Current] - key) - 32 + 3 * 95) % 95 + 32;
    return Crypted;
}

Upvotes: 0

Views: 3363

Answers (2)

Mantosh Kumar
Mantosh Kumar

Reputation: 5741

Please refer the following link to understand about this:

http://en.cppreference.com/w/cpp/string/basic_string/stol

stoi method throws the *std::invalid_argument* exception when no conversion could be performed. You may want to print before passing it into stoi(), and verify that whether string is valid or not.

std::cout<<keyString<<std::endl;

Upvotes: 1

yizzlez
yizzlez

Reputation: 8805

I am assuming the error is caused when you uncomment the code. Lets run through the error (you should be the one doing this, with your debugger) :

keyString = userInput.substr(locationOfFirstKeyIndex, locationSpace); 
//userInput is a blank string, lOFKI == 0 and so does locationSpace
stoi(keyString); //keyString is invalid, empty string

You should try getting your user input before parsing it...

Upvotes: 1

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