A file is a container in computer storage devices used for storing data. Show
Why files are needed?
Types of FilesWhen dealing with files, there are two types of files you should know about:
1. Text filesText files are the normal .txt files. You can easily create text files using any simple text editors such as Notepad. When you open those files, you'll see all the contents within the file as plain text. You can easily edit or delete the contents. They take minimum effort to maintain, are easily readable, and provide the least security and takes bigger storage space. 2. Binary filesBinary files are mostly the .bin files in your computer. Instead of storing data in plain text, they store it in the binary form (0's and 1's). They can hold a higher amount of data, are not readable easily, and provides better security than text files. File OperationsIn C, you can perform four major operations on files, either text or binary:
Working with filesWhen working with files, you need to declare a pointer of type file. This declaration is needed for communication between the file and the program.
Opening a file - for creation and editOpening a file is performed using the The syntax for opening a file in standard I/O is:
For example,
The file (both text and binary) should be closed after reading/writing. Closing a file is performed using the
Here, Reading and writing to a text fileFor reading and writing to a text file, we use the functions They are just the file versions of Example 1: Write to a text file
This program takes a number from the user and stores in the file After you compile and run this program, you can see a text file Example 2: Read from a text file
This program reads the integer
present in the If you successfully created the file from Example 1, running this program will get you the integer you entered. Other functions like Reading and writing to a binary fileFunctions Writing to a binary fileTo write into a binary file, you need to use the
Example 3: Write to a binary file using fwrite()
In this program, we create a new file We declare a structure
Now, inside the for loop, we store the value into the file using The first parameter takes the address of num and the second parameter takes the size of the structure Since we're only inserting one instance of num, the third parameter is Finally, we close the file. Reading from a binary fileFunction
Example 4: Read from a binary file using fread()
In this program, you read the same file In simple terms, you read one You'll get the same records you inserted in Example 3. Getting data using fseek()If you have many records inside a file and need to access a record at a specific position, you need to loop through all the records before it to get the record. This will waste a lot of memory and operation time. An easier way to get to the required data can be achieved using As the name suggests, Syntax of fseek()
The first parameter stream is the pointer to the file. The second parameter is the position of the record to be found, and the third parameter specifies the location where the offset starts. Different whence in fseek()
Example 5: fseek()
This program will start reading the records from the file Which mode should a file be opened in to allow data to be written to it erasing any previous data?When you open a file that file already exists on the disk using the 'w' mode, the contents of the existing file will be erased. The process of opening a file is only necessary with input files.
When a file that already exists is opened in append mode the files existing contents are erased?When a file that already exists is opened in append mode, the file's existing contents are erased. If you do not handle an exception, it is ignored by the Python interpreter, and the program continues to execute. You can have more than one except clause in a try/except statement.
What will happen when a program opens a file in write mode if the file doesn't exist?If you open a file for writing and the file doesn't exist, then the file is created with 0 length.
Where is the read position when a file is first opened for reading quizlet?The Read position of a file is the location of the next item that will be read from a file. When a file is first opened for reading then by default the read position of the file will begin at the first character of the file.
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