Thread: while loop trouble

Hey guys im trying to read in a file and list numbers to each line in the file but for some reason im getting a runtime logical error inside my while loop.

Code:

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

int main(int argc, char **argv)
{

    int line_no = 0;
    int input_char = 0;
    int nl = 1;
    FILE *fp;

    if(argc !=2) /* check for 2 arguments*/
    {

      fprintf(stderr, "invalid usage :%s\n", argv[0]);
      return 1; /* stop processing if failes */

    }

    if((fp = fopen(argv[1], "r")) == NULL) 
    /* opens file for reading and checks if it exists */
    {
     
     fprintf(stderr, "invalid usage: %s\n", argv[0]);
     return 1; /* stop processing if fails*/

    }


      while(input_char !=EOF)
 
          /* keep asking for input while not end of file*/
      {
          if ( nl )
          {
             printf("\n%d ", line_no);
             line_no++;
	  }
	  else
          { 
	     putc(input_char, stdout);
	     input_char = getc(fp);   
	     nl = input_char == '\n';
          }
    }
       
    

    fclose(fp);



    return EXIT_SUCCESS;

}

You are starting off with nl equal to 1, then in the while loop, you are checking if nl is true (non-zero). Since it is, it simply prints line_no then increases line_no. nl is not set to zero, so the while loop goes back again, nl is still 1.. so this goes on forever.