Question

how to declare a file pointer in C

Answer 1

#include<stdio.h>

int main()

{

 FILE *filepointer;

filepointer=fopen("example.txt","r");

if(filepointer==null){

printf("error: not to open file\n");

return 1;

}

return 0;

}

Answer 2

#include <stdio.h>

int main() {
   
    FILE *filePointer;

    filePointer = fopen("example.txt", "r");
    if (filePointer == NULL) {
        perror("Erro ao abrir o arquivo");
        return 1;
    }
    fclose(filePointer);

    return 0;
}

Answer 3

From https://cplusplus.com/reference/cstdio/FILE/

/* FEOF example */
#include <stdio.h>

int main()
{
   FILE * pFile;
   char buffer [100];

   pFile = fopen("myfile.txt", "r");
   if (pFile == NULL) perror("Error opening file");
   else
   {
       while (!feof(pFile))
       {
           if (fgets(buffer , 100 , pFile) == NULL) break;
           fputs(buffer , stdout);
       }
       fclose(pFile);
   }
   return 0;
}

The declaration of the file pointer is highlighted with yellow.