Why cannot I read string by fgets in C programming language?

Question

I have this code work :

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int main()
{
     FILE *File_fp = fopen("Example.dat", "w");
     char Temporary[50];
     if(!File_fp)
     {
        printf("An error occurred while creating the file.\n");
        exit(1);
     }

     fprintf(File_fp, "This is an example.\n");
     fgets(Temporary, 49, File_fp);

     printf("It was \"%s\"\n", Temporary);
     return EXIT_SUCCESS;
 }

I printed "This is an example." in the file, "Example.dat" and I want to read it again from the file by code above but there's no string in the output. Why? Please help me.

Answer 1

To read a file, you have to use the mode "r". Example: FILE *File_fp = fopen("Example.dat", "r");

And you made a mistake in this code. If it fails to create a file, fopen() function will return NULL. Then the value of the file pointer would be NULL. So, in your code if section will execute when the file is successfully created. So, change your code like this:

if(File_fp)
 {
  printf("An error occurred while creating the file.\n");
  exit(1);
 }

Just remove the (!) logical not sign.