#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 1024

/* push, pop, check function */

char stack[MAX_SIZE];
int stack_counter=0;

int push(char c) /* pushes character to top of the stack */
{
    if(stack_counter==1024) return 0;
    
    stack[stack_counter++]=c;
    return 1;
}

int pop() /* decrements stack_counter */
{
    if(stack_counter<0) return 0;
    
    stack_counter--;
    return 1;
}

int check (char c)
{
    char tmp;
    
    switch(c)
    {
       case '(':
       case '[':
       case '{':
            if((tmp=push(c)==0)) return 0;
            break;
       
       case ')':
            tmp=pop();
            if(tmp==0) return 0;
            if(stack[stack_counter]!='(') return 0;
            break;
            
       case ']':
            tmp=pop();
            if(tmp==0) return 0;
            if(stack[stack_counter]!='[') return 0;
            break;
            
       case '}':
            tmp=pop();
            if(tmp==0) return 0;
            if(stack[stack_counter]!='{') return 0;
            break;
            
       }
       return 1;
}
            

int main(int argc, char *argv[])
{
      
      int c;
      enum states { normal,
                    comment_entry, comment, comment_exit,
                    squote, squote_escape, squote2, squote3,
                    dquote, dquote_escape };
                    
      int line=1;
      int state=normal;
      int x=0;
      
      /*
      FILE *f;
      f = fopen("zad90.c", "r");
      if (f == NULL) return 1;
      */
      
      /*while((c=fgetc(f))!=EOF)*/
      while((c=getchar())!=EOF)
      {
          if(state==normal && c=='/') { state = comment_entry; }
          else if(state==normal && c=='"') { state = dquote; }
          else if(state==normal && c=='\'') { state = squote; }
          
          else if(state==normal) { if((check(c))==0) printf("Line %d: Mismatching %c\n", line, c); } 
          
          else if(state==comment_entry && c=='*') { state = comment; }
          else if(state==comment_entry && c=='/') { }
          else if(state==comment_entry) { state = normal;  if((check(c))==0) printf("Line %d: Mismatching %c\n", line, c); }  /* neccesary to check braces here aswell */
          
          else if(state==comment && c=='*') { state = comment_exit; }
          else if(state==comment) {}
          
          else if(state==comment_exit && c=='*') {}
          else if(state==comment_exit && c=='/') { state = normal; }
          else if(state==comment_exit) { state = comment; }
          
          else if(state==dquote && c=='"') { state = normal; }
          else if(state==dquote && c=='\\') { state = dquote_escape; }
          else if(state==dquote) { }
          
          else if(state==dquote_escape) { state = dquote; }
          
          else if(state==squote && c=='\'') { state = normal; printf("Line %d: Contant not properly closed.\n", line); }
          else if(state==squote && c=='\\') { state = squote_escape; }
          else if(state==squote) { state = squote2; }
          
          else if(state==squote_escape) { state = squote2; }
          
          else if(state==squote2 && c=='\'') { state = normal; }
          else if(state==squote2) { state = squote3; printf("Line %d: Contant not properly closed.\n", line); }
          else if(state==squote3 && c=='\'') { state = normal; }
          
          if(c=='\n') line++;
      }
          
          for(x=0; x<stack_counter; x++)
          printf("Mismatching %c\n", stack[x]);
          
          switch(state)
          {  
             case comment:
             case comment_exit:
                  printf("Code ends inside a comment.\n"); break;
             
             case dquote:
             case dquote_escape:
                  printf("Code ends inside \".\n"); break;
                  
             case squote:
             case squote_escape:
             case squote2:
                  printf("Code ends inside '.\n"); break;
                  
             default: printf("Code has no syntactic errors.\n"); break;
          }
          
          
          
      
  printf("Press any key to continue");
  getchar();	
  return 0;
}