模仿栈

 package untitled1;

public interface CharStackInterface {
    final int maxSize = 100;
    public void intStack();
    public char pop();
    public void push(char x);
    public boolean empty();
    public boolean full();
    public void clear();
}

class CharStack implements CharStackInterface {
    char[] data;
    int top;
    public CharStack() {
        data = new char[maxSize];
    }

    public void intStack() {
        top = -1;
    }

    public char pop() {
        if(!empty())
        {
            top --;
            return data[top+1];    
        }else
        {
            return '/0';
        }
    }

    public void push(char x) {
        if (!full()) {
            top++;
            data[top] = x;
        }
    }

    public boolean empty() {
        if (top == -1) {
            return true;
        } else {
            return false;
        }
    }

    public boolean full() {
        if (top == (100 - 1)) {
            return true;
        } else {
            return false;
        }
    }

    public void clear() {
        top = -1;
    }
}

 

public class Test {
  
    public static void main(String[] args) {
        CharStack cs = new CharStack();
        cs.intStack();
        cs.push('A');
        cs.push('B');
        cs.push('C');
        cs.push('D');
        cs.push('E');
        cs.push('F');
        System.out.println(cs.pop());
        System.out.println(cs.pop());
        System.out.println(cs.pop());
        System.out.println(cs.pop());
        System.out.println(cs.pop());
        System.out.println(cs.pop());

       
    }
}