xstak.cpp

本课程主要介绍面向对象程序设计的方法和c++语言的基本概念。以c++语言中的面向对象机制为主。学习者在学习过程中可以通过大量的程序实例和相关练习

// xstak.cpp
// demonstrates exceptions
#include <iostream>
using namespace std;
const int MAX = 3;              //stack holds 3 ints
////////////////////////////////////////////////////////////////
class Stack
   {
   private:
      int st[MAX];              //stack: array of integers
      int top;                  //index of top of stack
   public:
      class Range               //exception class for Stack
         {                      //note: empty class body
         };
//--------------------------------------------------------------
      Stack()                   //constructor
	      { top = -1; }
//--------------------------------------------------------------
      void push(int var)
	      {
         if(top >= MAX-1)       //if stack full,
            throw Range();      //throw exception
         st[++top] = var;       //put number on stack
         }
//--------------------------------------------------------------
      int pop()
	      {
         if(top < 0)            //if stack empty,
            throw Range();      //throw exception
         return st[top--];      //take number off stack
         }
   };
////////////////////////////////////////////////////////////////
int main()
   {
   Stack s1;

   try
      {
      s1.push(11);
      s1.push(22);
      s1.push(33);
//    s1.push(44);                        //oops: stack full
      cout << "1: " << s1.pop() << endl;
      cout << "2: " << s1.pop() << endl;
      cout << "3: " << s1.pop() << endl;
      cout << "4: " << s1.pop() << endl;  //oops: stack empty
      }
   catch(Stack::Range)                    //exception handler
      {
      cout << "Exception: Stack Full or Empty" << endl;
      }
   cout << "Arrive here after catch (or normal exit)" << endl;
   return 0;
   }