text: // Exercise 6-2.
  // Write a program that reads a C program and prints in alphabetical order
  // each group of variable names that are identical in the first 6 characters,
  // but different somewhere thereafter. Don't count words within strings and
  // comments. Make 6 a parameter that can be set from the command line.
  
  #include <stdio.h>
  
  int main()
  {
      fprintf(stderr, "not yet done\n");
      return 1;
  }
  