StackArray

public class StackArray {
    public static void main(String[] args) {
        StackA<Integer> stack = new StackA<>(10);
        stack.push(9);
        stack.push(5);
        stack.push(7);
        stack.push(2);
        stack.push(3);
        System.out.println(stack.isempty());
        System.out.println(stack.peek());
        System.out.println(stack.search(5));
        System.out.println(stack.pop());
    }
}
class StackA<T>{
    private Object[] data = null;
    private int maxsize = 0;
    private int top = -1;
    public StackA(){}
    public StackA(int i){
        if(i>=0){
            this.maxsize = i;
            data = new Object[i];
            top = -1;
        }else{
            throw new RuntimeException("初始化大小不能小于0");
        }
    }

    //进栈
    public boolean push(T e){
        if(top == maxsize-1){
            throw new RuntimeException("栈已满，无法将元素入栈");
        }else{
            data[++top] = e;
            return true;
        }
    }

    //查看栈顶元素但不移除
    public T peek(){
        if(top == -1){
            throw new RuntimeException("栈为空！");
        }else{
            return (T)data[top];
        }
    }

    //弹出栈顶元素
    public T pop(){
        if(top == -1){
            throw new RuntimeException("栈为空！");
        }else{
            return (T)data[top--];
        }
    }

    //判断是否为空栈
    public boolean isempty(){
        return top==-1 ? true : false;
    }

    //返回对象在栈中的位置
    public int search(T e){
        for(int i=0;i<top;i++) {
            if (data[i] == e)
                return ++i;
        }
        return -1;
    }
}