Csharp/CSharp Tutorial/Data Structure/Your Stack

A stack class for characters.

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()); 
    
  }   
}

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