Question

Theres an error on The bolded line, what am I doing wrong?

#include <iostream>
//just for writing and reading from console
#include <fstream>
//this one to deal with files, read and write to text files

using namespace std;

int main()
{
//first thing we need to read the data in the text file
//let's assume we have the reading in a text file called data.txt

//so, we need a stream input variable to hold this data

ifstream infile;
//now we copy the data from the file into this variable

infile.open("data.txt");

//now we have the text copied to this stream

//first thing we need to check if the file is open or not

if(!infile.eof())
//
{
cout<<"Error opening the file.";
return -1; //this line will end the program
}

//here we need to open the file that we will print
//the output to, that is the encrypted file

ofstream outfile;
outfile.open("out.txt"); //this will create an out file to write in later

//here we need to make a loop to change each character in the file
string line; //this will hold the string in each line in the infile

while(outfile.getline(line)) //this statement copies data
{
//here we make the encryption on the line, and then print it back into
//the output file
for(int i=0;i<line.length();i++)
{
line[i] += 3;
}
//now the line has been encrypted
//we pass it to the out file
outfile<<line<<endl; //just copy the line there and make a new line
}
//now we close both files
infile.close();
outfile.close();

}

Answer 1

#include <iostream> //just for writing and reading from console
#include <fstream>
#include <string>
//this one to deal with files, read and write to text files
using namespace std;

int main() {
//first thing we need to read the data in the text file
//let's assume we have the reading in a text file called data.txt
//so, we need a stream input variable to hold this data
    ifstream infile;
//now we copy the data from the file into this variable
    infile.open("data.txt");
//now we have the text copied to this stream
//first thing we need to check if the file is open or not
    if (!infile.eof())
//
    {
        cout << "Error opening the file.";
        return -1; //this line will end the program
    }
//here we need to open the file that we will print
//the output to, that is the encrypted file
    ofstream outfile;
    outfile.open("out.txt"); //this will create an out file to write in later
//here we need to make a loop to change each character in the file
    string line; //this will hold the string in each line in the infile
    while (getline(infile, line)) //this statement copies data
    {
//here we make the encryption on the line, and then print it back into
//the output file
        for (int i = 0; i < line.length(); i++) {
            line[i] += 3;
        }
//now the line has been encrypted
//we pass it to the out file
        outfile << line << endl; //just copy the line there and make a new line
    }
//now we close both files
    infile.close();
    outfile.close();
}