Handout 24c

A Small Inheritance Example*

// Original code by Dr. T.K. Prasad; modified by Venu Dasigi
// example of an integer stack

#include <iostream>
using namespace std;

class stack {
protected:                       // cannot be PRIVATE for subclassing 
	int  s[100];                 // sufficiently large 
	int  top;
public: 
	stack(void)         { top = -1; }
	void push(int c)    { s[++top] = c; }
	int  pop(void)      { return (s[top--]); }
	bool empty(void)    { return (top == -1); }
};

class bounded_stack : public stack  { 
private:
	int  limit;    // number of elements = limit+1
public: 
	bounded_stack(int size) : stack()  {limit = size - 1;}
	void push(int c)  { if (top < limit) stack::push(c);       
                          else cout << " ERROR: Stack Bound Exceeded" << endl;}
	bool full(void)    { return (top == limit); }               
};

void main(void) {
	int i, n;
	stack st;
    bounded_stack bst (3);  // one less than the number of elements pushed

	cout << endl;
	cout << " Input four (blank separated) integers: ";

	for(i=0;i<4;i++) {
		cin  >> n;
		st.push(n);
		bst.push(n);
	}

	cout << endl 
	     << " Integer List in Reverse (Stack):"; 

	while (! st.empty()) {        
		cout << st.pop() << " ";
	}

	cout << endl 
	     << " Integer List in Reverse (Bounded Stack):"; 

	while (! bst.empty()) {        
		cout << bst.pop() << " ";
	}

	cout << endl << endl;
}

// EXPECTED OUTPUT

/* 
 Input four (blank separated) integers: 22 33   44     55555       
 ERROR: Stack Bound Exceeded

 Integer List in Reverse (Stack):55555 44 33 22 
 Integer List in Reverse (Bounded Stack):44 33 22 
*/