Handout 4
Review of Files
1. Open a project, and a .cpp file.
2. Choose File, New from the menu and choose Text File. Once the text file is opened, go to the File menu again and choose the option that says “move” into the project. Your text file should show in the Solution Explorer Window.
3. Copy the following into your text file.
5
6
-9
22
3
4. Copy the following code into your source code.
#include<iostream>
//header
file needed for files
#include<fstream>
using namespace std;
int main()
{
//program to add
numbers from a file
//declarations
for file stream variables
ifstream
inFile;
ofstream
outFile;
//declarations
for other variables
int total = 0;
int inputVal;
inFile.open("data.txt"); //put the name of your text file in the quotes
outFile.open("out.txt"); //this file will be created when the program runs
//read from the
file
inFile
>> inputVal;
//do the loop
while there are still numbers in the file
while
(!inFile.eof())
{
total += inputVal;
inFile >> inputVal;
}
//output to the
standard output and to a file
cout
<< "The total is: "<<
total << endl;
outFile
<< "The total is: " <<
total << endl;
//close files
inFile.close();
outFile.close();
return
0;
}
5. Run your code.
What is the output?
6. Change your code
so that it only adds the positive numbers in the file.
7. Change your code
so that the main function only opens the files, calls a function that sums the
numbers, and closes the file.