Exercise 2

EOF Loops Exercise

Create a C++ program ex2_iodemo.cpp with the following code in the Visual Studio project or copy the following code into your IDE:

// Program IODemo demonstrates how to use EOF

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

int main()
{
    cout  << fixed  << showpoint;

float val;
    float sum = 0;
    float average = 0;
    int count = 0;
    ifstream inData;			// declares input stream
    ofstream outData;			// declares output stream

// binds program variable inData to file "inputfile.txt"
    inData.open("inputfile.txt");

//Testing the state of the stream
    //true means the last I/O operation on that stream succeeded
    //false means the last I/O operation on that stream failed
    if (!inData)
    {
        cout << "Can't open the input file successfuly." << endl;
        return 1;
    }

// binds program variable outData to file "outputfile.txt"
    outData.open("outputfile.txt");

//Testing the state of the stream
    if (!outData)
    {
        cout << "Can't open the output file successfuly." << endl;
        return 2;
    }

//Read value from the input file
    //Loop terminates when EOF is encountered

cout  << "The initial value for count is " << count  << ".  " << endl;
    cout << "Starting to process input file ... " << endl;

inData >> val;  //read in the first value
    while (inData)   //while previous read succeeded ...
    {
        // Add code: add the newly read value to the variable "sum"

// Add code: increment the counter "count".

// Add code: read the next value from the file into the variable "val"

}

if (count != 0 )
        average = sum / count;
    else
        average = 0;

// outputs sum, count  and average
    outData  << "The sum of the input values is " << sum  << "." << endl;
    outData  << "The number of valid input values is " << count  << "." << endl;
    outData  << "The average is " << average << "." <<endl;
    cout << "Output has been placed in the file: outputfile.txt" << endl;
    return 0;
}

This program uses file I/O to read floating point values from the data file inputfile.txt until the end of the file is reached. It then writes the sum and average of all the floating point numbers to the output file outputfile.txt.

Your assignment is to add the code to the while loop to read a number from the file, add it to the sum, and increment the counter. Look at the comments in the program to see where to put this code.

Instructions:

Complete the program according to the "Add code: " comments in the program.
Add 5 to 10 floating point numbers to a file called inputfile.txt. You may pick your own numbers. (You may have to create this file in your own IDE.)
Compile and run this C++ program. The output will be in the file outputfile.txt.

When you are done:

Take a screenshot of your IDE and console window after compiling and running the program.
For this exercise, you will have: ex2_iodemo.cpp, inputfile.txt and outputfile.txt files.

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