File Writing in C and C++ Quiz

File Input/Output in C

• Source_addr is the first address of the memory block where the data to be written is stored.
• Size is the number of bytes to be written.

Writing to Files in C

• fopen is used to open a file in write mode.
• fwrite is used to write data to a file.
• fclose is used to close the file after writing.

Reading from Files in C

• fopen is used to open a file in read mode.
• fread is used to read data from a file.
• fclose is used to close the file after reading.
• Methods to read from files:
  • fgetc to read a single character.
  • fgets to read a string.
  • fscanf to read formatted data.
  • fread to read a block of data.

Sample Programs in C

• Program to display the contents of a file on the screen:
  • Open the file for input.
  • Read characters from the file using fgetc.
  • Write the characters to the screen using printf.
  • Close the file.
• Program to read from a file until the end of file:
  • Open the file for input.
  • Use a while loop to read from the file until feof returns true.
  • Use fread to read a struct from the file.
  • Print the struct data to the screen using printf.
  • Close the file.

Full Methods

• writeC(): asks the user to enter a character, writes it to a file, and closes the file.
• readC(): opens a file, reads a character from the file, prints it to the screen, and closes the file.
• writeS(): asks the user to enter a string, writes it to a file, and closes the file.
• readS(): opens a file, reads a string from the file, prints it to the screen, and closes the file.

Opening and Closing Files

• If a file is not closed in the program, the operating system closes it at the end of the program execution.
• However, if the program terminates abnormally, data may be lost.

Reading and Writing

• Read(Source_file, Destination_addr, Size): reads data from a file.
• Write(Destination_file, Source_addr, Size): writes data to a file.