Csharp/CSharp Tutorial/Data Structure/Your Stack

A stack class for characters.

<source lang="csharp">using System;

class Stack {

 char[] stck; // holds the stack  
 int tos;     // index of the top of the stack  
  
 public Stack(int size) {   
   stck = new char[size]; // allocate memory for stack   
   tos = 0;   
 }   
 
 public void push(char ch) {   
   if(tos==stck.Length) {   
     Console.WriteLine(" -- Stack is full.");   
     return;   
   }   
      
   stck[tos] = ch;  
   tos++;  
 }   
  
 public char pop() {   
   if(tos==0) {   
     Console.WriteLine(" -- Stack is empty.");   
     return (char) 0;    
   }   
    
   tos--;   
   return stck[tos];   
 } 

 public bool full() { 
   return tos==stck.Length;    
 } 

 public bool empty() { 
   return tos==0; 
 } 

 public int capacity() { 
   return stck.Length; 
 } 

 public int getNum() { 
   return tos; 
 } 

} class MainClass {

 public static void Main() {   
   Stack stk1 = new Stack(10);   
   Stack stk2 = new Stack(10);   
   Stack stk3 = new Stack(10);   
   char ch;   
   int i;   
  
   Console.WriteLine("Push A through J onto stk1."); 
   for(i=0; !stk1.full(); i++)   
     stk1.push((char) ("A" + i));   
 
   if(stk1.full()) 
      Console.WriteLine("stk1 is full."); 

   Console.Write("Contents of stk1: ");   
   while( !stk1.empty() ) {    
     ch = stk1.pop();   
     Console.Write(ch);   
   }   
  
   Console.WriteLine();   

   if(stk1.empty()) 
      Console.WriteLine("stk1 is empty.\n"); 
  
   Console.WriteLine("Again push A through J onto stk1."); 
   for(i=0; !stk1.full(); i++)   
     stk1.push((char) ("A" + i));   

   Console.WriteLine("Now, pop chars from stk1 and push " + 
                     "them onto stk2."); 
   while( !stk1.empty() ) {    
     ch = stk1.pop();   
     stk2.push(ch); 
   }   

   Console.Write("Contents of stk2: ");   
   while( !stk2.empty() ) {    
     ch = stk2.pop();   
     Console.Write(ch);   
   }   


   Console.WriteLine("Capacity of stk2: " + stk2.capacity()); 
   Console.WriteLine("Number of objects in stk2: " + 
                     stk2.getNum()); 
   
 }   

}</source>

Push A through J onto stk1.
stk1 is full.
Contents of stk1: JIHGFEDCBA
stk1 is empty.
Again push A through J onto stk1.
Now, pop chars from stk1 and push them onto stk2.
Contents of stk2: ABCDEFGHIJCapacity of stk2: 10
Number of objects in stk2: 0