Question

In this function I need to replace all chars in a file that is inputted, e.g. an a, with another char inputted, e.g. an i. I have given it two shots but as I am new and it’s way too late for my brain to even work any advice?

void swapping_letter()
{
ifstream inFile("decrypted.txt");   

char a;
char b;
string line;

if (inFile.is_open())
{
    while (!inFile.eof())
    {
        getline(inFile,line);
    }

    cout<<"What is the letter you want to replace?"<<endl;
    cin>>a;             
    cout<<"What is the letter you want to replace it with?"<<endl;
    cin>>b;

    replace(line.begin(),line.end(),a,b);


            inFile<<line


    inFile.close();

}
else
{
    cout<<"Please run the decrypt."<<endl;
}
}

or:

void swapping_letter()
{
ifstream inFile("decrypted.txt");   

char a;
char b;

if (inFile.is_open())
{
    const char EOL = '\n';                                          
    const char SPACE = ' ';

    cout<<"What is the letter you want to replace?"<<endl;
    cin>>a;             
    cout<<"What is the letter you want to replace it with?"<<endl;
    cin>>b;

    vector<char> fileChars;                                     
    while (inFile.good())                                            
    {
        char c;
        inFile.get(c);
        if (c != EOL && c != SPACE)                             
        {
            fileChars.push_back(c);
        }


        replace(fileChars.begin(),fileChars.end(),a,b);

        for(int i = 0; i < fileChars.size(); i++)
        {
            inFile<<fileChars[i];
        }
    }
}
else
{
    cout<<"Please run the decrypt."<<endl;
}
}

Answer 1

One way of doing this is to read the original file, replace characters and write the output to a new file.

Then eventually when you are done probably overwrite the old file with the new.