#include<iostream.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>
#include<process.h>
#include<iomanip.h>
   struct node
       {
	int data;
	node *next;
	 };
	node *top;
	//node *s;
   void initialize()
   {
     top=NULL;
   }

    void push(int x)
    {
	node *p=new node;
	if(p!=NULL)
	 {
	    if(top==NULL)
	     {
	      p->data=x;
	       p->next=NULL;
	       top=p;
	     }
	   else
	      {
	      p->next=top;
	      top=p;
	     }
	 }
	   else
	      {
       cout<<"\t\tError! The system run out of memory"<<endl;
       exit(1);
     }
  cout<<top->data;
}

    int pop()
    {
     node *p=top;
      if(top!=NULL)
      {
       top=p->next;
	return p->data;
      }
    cout<<"\t\tError! The stack is empty"<<endl;
    return 0;
   }

void main()
   {
     clrscr();
     int value,x; int y,z;

     initialize();
     const int size=50;
     int e[size];
    cout<<"\n\n\t\t\tEnter Postfix expression\n"<<endl;
    cout<<"\n\n\t\t\t============================="<<endl;
	 cin.getline(e,100)
    for(int i=0;i<strlen(e);i++)
      {
             if(e!='\0')
          if((e[i]>='0')&&(e[i]<='9'))
            {
              int x;
	     x=<int>(e[i]);//casting
            push(x);
          }
      else if(e[i]=='+' || e[i]=='*' || e[i]=='-' || e[i]=='/')
             {
              y=pop();
              z=pop();
            }
	  if(e[i]=='+')
            {
	     value=y+z;
	     push (value);
           }
     else if(e[i]=='-')
          {
	   value=y-z;
	   push (value);
         }
     else if(e[i]=='*')
          {
           value=y*z;
           push (value);
        }
	else if(e[i]=='/')
	     {
	       value=y/z;
	       push (value);
	   }
  }
  getch();
  }