Question

HW_6a - Read a text file

1. Create a new C++ project and name it as:   Numbers
2. Create a text file and

    save it as:   data.txt

• Create and save the file

     in a C++ project

     in the Resource folder.

1. Enter the following numbers:        3

                                                             4

                                                             5       Note:   After you enter the 5, don’t press the enter key.

1. Save and close the file.

1. Add another file and name it:   Source.cpp

1. Write one statement that declares a file object and opens it for reading.

1. Include code that checks to see if the file opened successfully.

• If the file does not open, the program should display:   Error opening file!
  • The program should then close.

• Use a while loop to read the text file and output the numbers to the screen.

   (See OUTPUT below)

• The while loop should read the file until the endof-file marker is encountered.
• One number is read and displayed each iteration.

/* OUTPUT

Here are the numbers in the file:

     3

     4

     5

Press any key to continue . . . */

Please make this code based on C++, and write a description for each code.

Answer 1

Numbers.cpp

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

int main () {
    ofstream myfile ("data.txt");
    int a, b, c;
    if (myfile.is_open())
    {
        cout << "Enter the three numbers: \n";
        cin >> a;
        cin >> b;
        cin >> c;
        myfile << a << endl;
        myfile << b << endl;
        myfile << c << endl;
        myfile.close();
    }
    else cout << "Error opening file!";
    return 0;
}

Output:

Source.cpp

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

int main () {
    string line;
    ifstream myfile ("data.txt");
    if (myfile.is_open())
    {
        // OUTPUT
        cout << "Here are the numbers in file: \n";
        while ( getline (myfile,line) )
        {
            cout << line << '\n';
        }
        myfile.close();
    }

    else cout << "Error opening file!"; 

    return 0;
}

Output:

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