练习代码
class Solution {
public boolean isValid(String s) {
aboutStack();
return true;
}
public void aboutStack(){
// 初始化栈,数据类型为 Integer
Stack<Integer> s = new Stack<Integer>();
// 练习栈的 5 个基本操作
// 1、push(x)
s.push(1);
s.push(2);
s.push(3);
System.out.printf("s = %s \n ",s.toString());
System.out.printf("--------------\n");
// 2、top(),在 Java 中 Stack 这个类是使用 peek 获取栈顶元素的
System.out.printf("s.top() = %d \n ",s.peek());
System.out.printf("--------------\n");
// 3、pop()
s.pop();
System.out.printf("s = %s \n ",s.toString());
s.pop();
System.out.printf("s = %s \n ",s.toString());
System.out.printf("--------------\n");
// 4、empty()
if(s.isEmpty()){
System.out.printf("s is empty!\n");
}else{
System.out.printf("s is not empty!\n");
}
System.out.printf("--------------\n");
// 5、size()
System.out.printf("s = %s \n ",s.toString());
System.out.printf("s.size = %d \n ",s.size());
System.out.printf("--------------\n");
}
}