C - File Handling - Read and Write Characters

In this tutorial we will learn to read and write characters in files in C programming language.

We have already learned how to create files in C in the previous tutorial. Feel free to check that out.

The getc and putc I/O functions

We use the getc() and putc() I/O functions to read a character from a file and write a character to a file respectively.

Syntax of getc:

char ch = getc(fptr);

Where, fptr is a file pointer.

Note! EOF marks the End-Of-File. And when we encounter EOF character it means we have reached the end of the file.

Syntax of putc:

putc(ch, fptr);

Where, ch is the character to write and fptr is a file pointer.

Write a program in C to create a new file and save user name taken as input from the user

For this we will first create a FILE pointer and create a file by the name username.txt. Feel free to use any other filename that you like.

Then we will use the putc() function to write the characters in the file.

Once that is done we can then use the getc() function to read the file data till we hit the EOF and show it in the console.

Complete code:

#include <stdio.h>

int main(void) {
  // creating a FILE variable
  FILE *fptr;
  
  // creating a character variable
  char ch;
  
  // open the file in write mode
  fptr = fopen("username.txt", "w");
  
  // take user input
  printf("Enter your name: ");
  
  // keep reading the user input from the terminal
  // till Return (Enter) key is pressed
  while( (ch = getchar()) != '\n' ) {

    // write character ch in file
    putc(ch, fptr);

  }
  
  // close the file
  fclose(fptr);
  
  // open the file in read mode
  fopen("username.txt", "r");
  
  // display the content of the file
  printf("\nFile content:\n");
  while( (ch = getc(fptr)) != EOF ) {
    printf("%c", ch);
  }

  printf("\nEnd of file\n");
  
  // close file
  fclose(fptr);
  
  return 0;
}

Output:

Enter your name: Yusuf Shakeel

File content:
Yusuf Shakeel
End of file

Content of the file: