Question

Using C, 
Write a program to alphabetically merge the three word list files (american0.txt, american1.txt, and american2.txt). Each file will have words in random order. The output must be a file called words.txt.

Note that you cannot cheat by using Linux commands to do this. It must be done entirely in your C code.

File format:
apple
banana
pear
  .
  .
  .

Hint:
Program will need to utilize double pointers.

More Hints:
1. Assume no word is bigger that 50 characters.
2. Determine file sizes first.
3. Create a single dynamic array to hold all of the words.
4. Write result to words.txt.
5. man 3 malloc or calloc.
6. man 3 strcmp and strcpy.
7. man 3 feof.

Answer 1

#include <stdio.h>

#include <stdlib.h>   

int main()

{

   int X = 1024 * 1024 - 1;

   FILE *f1 = fopen("american0.txt", "r");

 fseek(f1, X , SEEK_SET);

   FILE *f2 = fopen("american1.txt", "r");

 fseek(f2, X , SEEK_SET);

  FILE *f3 = fopen("american3.txt", "r");

fseek(f3, X , SEEK_SET);

FILE *f4 = fopen("words.txt", "w");

   char c;

  

   if (f1 == NULL || f2 == NULL || f3 == NULL || f4==NULL)

   {

         puts("Couldn't open files");

         exit(0);

   }

   while ((c = fgetc(f1)) != EOF)

      fputc(c, f4);

   while ((c = fgetc(f2)) != EOF)

      fputc(c, f4);

   while ((c = fgetc(f3)) != EOF)

      fputc(c, f4);

printf("Success");

   fclose(fp1);

   fclose(fp2);

   fclose(fp3);

   return 0;

}