#include <stdio.h>

void main() {
  char buff[256];
  FILE* read_f = fopen("./sample.txt", "r");
  
  int line_num = 1;
  while (fgets(buff, 256, read_f) != NULL) {
    printf("%d:%s", line_num, buff);
    line_num++;
  }

  fclose(read_f);
}