Open and read a file in c example

Popular Tutorials Data Types in C. C for Loop. Arrays in C Programming. Pointers in C. Find roots of a quadratic equation. Print Pyramids and Patterns. Check prime number. Print the Fibonacci series. Reference Materials string. Start Learning C. Explore C Examples. Related Topics Write a Sentence to a File. Read the First Line From a File. C clearerr. Display its own Source Code as Output. C "Hello, World! C File Handling In this tutorial, you will learn about file handling in C.

A file is a container in computer storage devices used for storing data. Why files are needed? When a program is terminated, the entire data is lost. Storing in a file will preserve your data even if the program terminates. So when we called second open , then first unused fd is also 3. So, output of this program is 3. A successful read updates the access time for the file. Also, some times read system call should read less bytes than cnt. Those bytes are as follows: 0 0 0 foo. Suppose that foobar.

Then what is the output of the following program? Skip to content. Change Language. Related Articles. Table of Contents. For an example that uses StreamReader , see How to read a text file one line at a time.

The files that are used in this example are created in the topic How to write to a text file. If you are not using the text files from How to write to a text file , replace the argument to ReadAllText and ReadAllLines with the appropriate path and file name on your computer. Do not rely on the name of a file to determine the contents of the file.

For example, the file myFile. In order to read the information from the file, we need to first open it. The opening of the file is done using ofstream or fstream object of the file. Hence, we need to specify the mode of file opening along with the file name. But still it is considered to be a good practice to close the file after the desired operation is performed.

In order to read or write the file, we need to first open the file using the open function and define its mode. In order to release all the resources and free the allocated memory close function is used. We have used the if and else statement to check whether the file is [resent or not. If the file is not found, a proper message is displayed on the console.