C program to read a file

C program to read a file: This program reads a file entered by the user and displays its contents on the screen, fopen function is used to open a file it returns a pointer to structure FILE. FILE is a predefined structure in stdio.h . If the file is successfully opened then fopen returns a pointer to file and if it is unable to open a file then it returns NULL. fgetc function returns a character which is read from the file and fclose function closes the file. Opening a file means we bring file from disk to ram to perform operations on it. The file must be present in the directory in which the executable file of this code sis present.

C program to open a file

C programming code to open a file and to print it contents on screen.

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
   char ch, file_name[25];
   FILE *fp;
 
   printf("Enter the name of file you wish to see\n");
   gets(file_name);
 
   fp = fopen(file_name,"r"); // read mode
 
   if( fp == NULL )
   {
      perror("Error while opening the file.\n");
      exit(EXIT_FAILURE);
   }
 
   printf("The contents of %s file are :\n", file_name);
 
   while( ( ch = fgetc(fp) ) != EOF )
      printf("%c",ch);
 
   fclose(fp);
   return 0;
}

Download Read file program.

Output of program:
read file

There are blank lines present at end of file. In our program we have opened only one file but you can open multiple files in a single program and in different modes as desired. File handling is very important when we wish to store data permanently on a storage device. All variables and data of program is lost when program exits so if that data is required later we need to use files.