#include <stdio.h>
#include <stdlib.h> //exit()
#include <string.h> //strlen()

#define MAX_LEN 256

int main(int argc, char **argv)
{
  FILE *fp;
  char string[MAX_LEN];
  int n = 1;
  const char *filename;

  if(argc > 1) {
    filename = argv[1];
  } else{
    filename = "./test.txt";
  }
  if ((fp = fopen(filename, "r")) == NULL) {
    fprintf(stderr, "can't open %s\n",filename);
    exit(2);
  }
  
  while((fgets(string, MAX_LEN - 1, fp)) != NULL) {
    string[strlen(string) - 1] = '\0';
    printf("%d:",n++);
    puts(string);
  }
  fclose(fp);

  return 0;
}