Text files

1. What we want to do is to test our ability to write to a text file and later read from it. Suppose we wrote a program like the following:

(just the main body)

int n1 = 3;

int n2 = 10;

ofstream outFile;

outFile.open(test.txt);

outFile << n1 << endl;

outFile << n2 << endl;

outFile.close();

ifstream inFile;

inFile.open (test.txt);

inFile >> n1;

inFile >> n2;

inFile.close();

cout << n1: << n1 << endl;

cout << n2: << n2 << endl;

If you ran this and it printed out 3 for n1 and 10 for n2, is this proof that your program correctly wrote to a text file and then read from it? If you think so, try copying it and running it.

2. After it runs, try modifying the second file name test.txt to abc.txt and see how it runs. Whats going on?

3. Add test.txt to resource files in your project. Where was the file located? If you were going to add a file to a project for reading data, what directory would you put that file in? Did you find abc.txt in this directory?

4. Change the type of the variable to be an integer and a float. Initialize these variables to interesting values such as 12345 and 88.9922. Rerun the program after making any modifications to get it to run.

5. Reverse the order of reading the values from the file. What is the result and why?

6. Take away lessons:

1. The direction that a file should be located so that it can be opened and read is: _______________________

2. File open should be tested every time a file is opened so that we will not assume that a file is open when it is not. If a file is not correctly opened, we want to receive a message indicating this.

3. The order in which data is extracted from a file is critical to it being accurately extracted.