FixedCapacityStackOfStrings

/******************************************************************************
 *  Compilation:  javac FixedCapacityStackOfStrings.java
 *  Execution:    java FixedCapacityStackOfStrings
 *  Dependencies: StdIn.java StdOut.java
 *
 *  Stack of strings implementation with a fixed-size array.
 *
 *  % more tobe.txt
 *  to be or not to - be - - that - - - is
 *
 *  % java FixedCapacityStackOfStrings 5 < tobe.txt
 *  to be not that or be
 *
 *  Remark:  bare-bones implementation. Does not do repeated
 *  doubling or null out empty array entries to avoid loitering.
 *
 ******************************************************************************/

import edu.princeton.cs.algs4.StdIn;
import edu.princeton.cs.algs4.StdOut;

public class FixedCapacityStackOfStrings {

    private String[] a;  // holds the items
    private int N;       // number of items in stack

    // create an empty stack with given capacity
    public FixedCapacityStackOfStrings(int capacity) {
        a = new String[capacity];
        N = 0;
    }

    public boolean isEmpty()            {  return N == 0;                    }
    public boolean isFull()             {  return N == a.length;             }
    public void push(String item)       {  a[N++] = item;                    }
    public String pop()                 {  return a[--N];                    }


    public static void main(String[] args) {
        int max = Integer.parseInt(args[0]);
        FixedCapacityStackOfStrings stack = new FixedCapacityStackOfStrings(max);
        while (!StdIn.isEmpty()) {
            String item = StdIn.readString();
            if (!item.equals("-")) stack.push(item);
            else if (stack.isEmpty())  StdOut.println("BAD INPUT");
            else                       StdOut.print(stack.pop() + " ");
        }
        StdOut.println("\n");

        // print what's left on the stack
        StdOut.print("Left on stack: ");
        while (!stack.isEmpty()) {
            StdOut.print(stack.pop() + " ");
        }

        StdOut.println();
    }
}