Reading the contents from a file

Question

I want to save the contents of a .txt file into an array. The thing here is I am using the location first into another array and I want to use that array holding my location to store the contents of the file into an array. The code doesn't seem to work. Help appreciated.

#include <stdio.h>
#include <string.h>
int main()
{
   char location[50],input[1000]={0};
   int i=0; 
   printf("Enter your file location:\n");
   scanf("%999[^\n]",location);

   FILE *ptr;
   ptr = fopen("location", "r");

   while(!EOF)
   {
     char c;
     c = (char) fgetc(ptr);
     input[i] = c;
     printf("%c", input[i]);
     i++;
   }
   input[i] = NULL;
   printf("%s",input);
   getch();
   return 0;
}

Answer 1

EOF is something different (it's a macro, and thus !EOF is always a constant value, and doesn't actually check anything). Perhaps you meant to use feof(). Or, rather:

int c;
while ((c = fgetc(ptr)) != EOF)
{
    ...

Answer 2

Multiple problems

1. Wrong size in scanf() for buffer and result should be tested.

   char location[50];
   // scanf("%999[^\n]",location);
   if (1 != scanf("%49[^\n]",location)) HandleError();
   

2. Wrong parameter to fopen() (@Mat). Add test

   // ptr = fopen("location", "r");
   ptr = fopen(location, "r");
   if (ptr == NULL) HandleOpenError();
   

3. Wrong use of EOF and c type (@Cornstalks)

   // while(!EOF) {
   //  char c;
   // c = (char) fgetc(ptr);
   int c;
   while ((c = fgetc(ptr)) != EOF) {
   

4. Wrong termination.

   // input[i] = NULL;
   input[i] = '\0';
   

5. UB if file length >= 1000;
   Check @Fiddling Bits answer for allocating a buffer for whole file.
   Suggest size_t fileLength instead of long int fileLength.
   Add free(pFileContents);

6. No fclose()

    fclose(ptr);
    return 0;
   

7. Minor: printf("%s",input); will not print out the entire file if text file is unusual and has embedded \0.

Answer 3

First, you must determine the length of the file:

fseek(ptr, 0, SEEK_END);
long int fileLength = ftell(ptr);

Then, create an buffer large enough to hold the full contents of the file:

char *pFileContents = malloc(fileLength);
if(!pFileContents)
    return -1; // Error

Lastly, copy the contents of the file to the newly created buffer:

rewind(ptr);
if(fread(pFileContents, 1, fileLength, ptr) != fileLength)
    return -1; // Error
fclose(ptr);