学习记录7

栈
import java.util.Stack;

public class StackExample {
public static void main(String[] args) {
Stack stack = new Stack<>();

    // 入栈操作
    stack.push(10);
    stack.push(20);
    stack.push(30);

    // 查看栈顶元素
    System.out.println("栈顶元素: " + stack.peek());

    // 出栈操作
    int popped = stack.pop();
    System.out.println("出栈元素: " + popped);

    // 再次查看栈顶元素
    System.out.println("栈顶元素: " + stack.peek());
}

}