#include <iostream>
 using namespace std;
#include <string.h>
#include <string>
#include <queue>
typedef queue<char*> CHARQUEUE;   
const int MyArray = 100;  
void InputFunction(char []); 
void lex(char *);      
void syntax();         
CHARQUEUE Subject; 
CHARQUEUE Verb;    
CHARQUEUE Object;  
void main()   
{
  char UserInput[MyArray];
  cout <<"Enter the sentence"<<endl <<"(E) to exit" << endl;
  cin.getline(UserInput, MyArray); 
  InputFunction(UserInput);  
  syntax();
  if (!Subject.empty())
  {
  cout << Verb.front() << endl;
  Verb.pop();
  }
  main();
}
void InputFunction(char mySentence[]) 
{
 char *tokenPtr, *nullPtr = NULL;
 tokenPtr = strtok(mySentence, " ");
 while (tokenPtr != NULL)
 {   
        lex(tokenPtr);    
  tokenPtr = strtok(nullPtr, " ");
 }
}  
 
void lex(char *str)
{
   if ((strcmp(str, "A") ==0)  || (strcmp(str, "The")==0))
   {
    Subject.push(str);
   }
   else if ((strcmp(str,"cat") == 0) || (strcmp(str,"rat")== 0) || (strcmp(str,"mat")== 0))
   { 
      cout <<strcmp(str,"cat") << endl;
      Subject.push(str); 
   }
   else if (strcmp(str, "I")==0)
   {
      Subject.push(str);
      Subject.push("firstperson");
   }      
   else if (strcmp(str,"like")==0 || strcmp(str, "am")==0 || strcmp(str,"see")==0)
   {
      Verb.push(str);
      Verb.push("firstperson");
   }
   else if (strcmp(str,"likes")==0 || strcmp(str,"is")==0 || strcmp(str, "sees")==0)
   {
   Verb.push(str);
   Verb.push("thirdperson");
   }      
   else if (strcmp(str,"a")==0 || strcmp(str, "the")==0)
   {
      Object.push(str);
   }
   else if (strcmp(str,"cat")==0 || strcmp(str,"rat")==0 || strcmp(str,"mat")==0)
   {
 
    if (strcmp(Object.back(), "a")==0 || strcmp(Object.back(), "the")==0)
   {
       Object.push(str);  
   }
   }
   else if (strcmp(str, "me")==0)
   {
      Object.push(str);
   }
   else 
   {
      cout << "String is not accepted." <<endl;
   exit(0);
   }
 }
void syntax()
{
 if (!Subject.empty() && !Verb.empty())
 if(strcmp(Verb.back(),Subject.back())==0)
 {
  cout <<"String is correct" <<endl;
 }
 else 
  cout <<"String is not accepted." <<endl;
}