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Encryption/Decryption program issue

closed account (oNC9Nwbp)
I think the getline on line 17 and 67 is incorrect because the program shows both the "Enter a message" and "Enter key" on the same line (when ran) and does not allow for a message to be entered, only the key. I need it to be able to do both as this is an encryption/decryption program. Any help would be appreciated.

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#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    string choice;
        cout << "Do you want to Encrypt or Decrypt? "<< endl;
        cin >> choice;
//encryption code here
if (choice== "encrypt")
{
    char text[100], ch;
    int i, key;

    cout<< "Enter a Message to Encrypt: ";
    cin.getline(text, 100);
    cout<< "Enter Key: ";
    cin>> key;

    for(i= 0; text[i]!= '\0'; i++)
    {
        ch= text[i];

        if(ch>= 'a'&& ch<= 'z')
        {
            ch= ch+ key;

            if(ch> 'z')
            {
                ch= ch- 'z'+ 'a'- 1;
            }

            text[i]= ch;

        }
        else if(ch>= 'A'&& ch<= 'Z')
        {
            ch= ch+ key;

            if(ch> 'Z')
            {
                ch= ch- 'Z'+ 'A'- 1;
            }

            text[i] = ch;
        }
    }

    cout<< "Encrypted Message: "<< text;

    ofstream fileEnc;
    fileEnc.open ("Encryption.txt");
    fileEnc<< text;
    fileEnc.close();


}
//decryption code here
else
    {

    char text[100], ch;
    int i, key;

    cout<< "Enter a Message to Decrypt: ";
    cin.getline(text, 100);
    cout<< "Enter Key: ";
    cin>> key;

    for(i= 0; text[i]!= '\0'; i++)
    {
        ch= text[i];

        if(ch>= 'a'&& ch<= 'z')
        {
            ch= ch- key;

            if(ch< 'a')
            {
                ch= ch+ 'z'- 'a'+ 1;
            }

            text[i] = ch;
        }
        else if(ch>= 'A'&& ch<= 'Z')
        {
            ch= ch- key;

            if(ch> 'a')
            {
                ch= ch+ 'Z'- 'A'+ 1;
            }

            text[i]= ch;
        }
    }

    cout<< "Decrypted Message: "<< text;

    ofstream fileDec;
    fileDec.open ("Decryption.txt");
    fileDec<< text;
    fileDec.close();

    }
    return 0;
}
Last edited on
mbozzi (3928)
Check line 19. key is defined as an int: is that what you enter?

If you do not enter an int, then the stream std::cin enters a failure state, which causes all further attempts to read from the stream to fail immediately.
closed account (oNC9Nwbp)
Yes the key for my encryption is an integer. This is a caesar cipher and it moves the letters X amount over.

Example(also the way it should be entered when the program is run):
Question: Do you want to encrypt or decrypt?
Answer: Encrypt
Please enter message: Hello!
Enter Key: 1
New Message: Ifmmp!

what the program does:

Do you want to encrypt or decrypt?
Answer: Encrypt
Please enter message: Enter Key: 1
New Message:


The program doesnt even give you the option to put something in for the message. I had it working originally without the if statement but when i added that it started messing up.
tpb (1495)
Is it because you're reading choice with >> ? That leaves the newline in the input stream so the first getline after that reads an empty string. Try reading choice with getline to ensure the newline is eaten.
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