/*a HQ9+ parser. Use it to make good game*/#include <stdio.h>const char helloworld[] = "Hello, world!";const unsigned int bottles = 99;unsigned long theaccumulator = 0;void feature_H(FILE* file){   printf("%s\n", helloworld);}void feature_Q(FILE* file){   char ch;   long int back = ftell(file);   fseek(file, 0, SEEK_SET);   while((ch = fgetc(file)) != EOF)      fputc(ch, stdout);   fputc('\n', stdout);   fseek(file, back, SEEK_SET);}void feature_9(FILE* file){   unsigned int cont = bottles;   while(cont > 0)   {      printf("%d bottle%sof beer on the wall,\n"      "   %d bottle%sof beer.\n"      "   Take one down, pass it around,\n",      cont, cont > 1 ? "s ":" ", cont, cont > 1 ? "s ":" ");      --cont;      if(cont == 0) printf("   no more bottles of beer on the wall.\n\n");      else printf("   %d bottle%sof beer on the wall.\n\n", cont, cont > 1 ? "s ":" ");   }}void feature_PLUS(FILE* file){   ++theaccumulator;}int main(int argc,char *argv[]){   FILE* filein;   char ch;   if(argc == 1)   {      fprintf(stderr,"Usage: %s filename.hq9+\n",argv[0]);      return 1;   }   filein = fopen(argv[1], "r");   if(!filein)   {      fprintf(stderr,"Cannot open input file\n");      return 1;   }   fseek(filein, 0, SEEK_SET);   while((ch = fgetc(filein)) != EOF)   {      switch(tolower(ch))      {         case 'h':            feature_H(filein);            break;         case 'q':            feature_Q(filein);            break;         case '9':            feature_9(filein);            break;         case '+':            feature_PLUS(filein);            break;         default:            fprintf(stderr, "Parser error: invalid (%c) instruction", ch);            fclose(filein);            return 1;      }   }   fclose(filein);   return 0;}