package suanfuyouxian2;

//Stack.java
// demonstrates stacks
// to run this program: C>java StackApp
import java.io.*; // for I/O
////////////////////////////////////////////////////////////////
class Stack
{
private int maxSize; // size of stack array
private char[] stackArray;
private char top; // top of stack
//-------------------------------------------------------------

public Stack(int s) // constructor
{
maxSize = s; // set array size
stackArray = new char[maxSize]; // create array
top = '#'; // no items yet
}
//-------------------------------------------------------------

public void push(char j) // put item on top of stack
{
stackArray[++top] = j; // increment top, insert item
}
//-------------------------------------------------------------

public char pop() // take item from top of stack
{

return stackArray[top--]; // access item, decrement top
}
//-------------------------------------------------------------

public char peek() // peek at top of stack
{
return stackArray[top];
}
//-------------------------------------------------------------

public boolean isEmpty() // true if stack is empty
{
return (top == '#');
}
//-------------------------------------------------------------

public boolean isFull() // true if stack is full
{
return (top == maxSize-1);
}
//-------------------------------------------------------------

} // end class StackX
////////////////////////////////////////////////////////////////