Question

This function takes in a string as an argument and then enciphers the numbers and should write an enciphered string to a file. eText in the main seems to not be getting anything from the function and I cannot figure out why.

Function Definition:

string Encipherer::encipherer(string plainMessage){

    int i = plainMessage.length();
    string eMessage;

    cout << i << endl;

    for(i = 0; i >= plainMessage.length(); i++){
            if(plainMessage[i] >= 65 && plainMessage[i] <= 90){
                    if(plainMessage[i] + shift > 90){
                            eMessage[i] += plainMessage[i] - 26 + shift;
                    }

                    else{
                            eMessage += plainMessage[i] + shift;
                    }
            }

            else if(plainMessage[i] >= 97 && plainMessage[i] <= 122){
                    if(plainMessage[i] + shift > 122){
                            eMessage[i] += plainMessage[i] - 26 + shift;
                    }
                    else{
                            eMessage += plainMessage[i] + shift;
                    }
            }
}

            else{
                    eMessage += plainMessage[i];
            }

}
return eMessage;
}

Main Function:

int main(){

string plainMessage, eText;
string fileName = "inputText.txt";
ofstream outputText;
        outputText.open ("outputText.txt");

Encipherer E(5);

plainMessage = E.encipherFromFile(fileName);

eText = E.encipherer(plainMessage);

outputText << eText;

outputText.close();


return 0;
}

Thanks in advance!

Answer 1

In Encipherer::encipherer

for(i = 0; i >= plainMessage.length(); i++){

should be

for(i = 0; i < plainMessage.length(); i++){

Also, in both if blocks:

                    eMessage[i] += plainMessage[i] - 26 + shift;

should become

                    eMessage += plainMessage[i] - 26 + shift;

Is shift defined on some other place? And you seem to have a } before the last else that shouldn’t be there, if the code is copied correctly.