棧_對錶達式求值

題目：“+”表示將後面的字母壓入棧，“-”表示彈出棧頂字母並打印它。

import java.util.Scanner;
import java.util.Stack;

public class A {
    //+U+n+c-+e+r+t---+a-+i-+n+t+y--+z-+r+u---+l+e+s--
    public static void main(String[] args) {
        System.out.print("請輸入：");
        Scanner in = new Scanner(System.in);
        String inputString = in.nextLine();
        char[] aa = inputString.toCharArray();

        Stack<Character> stack1 = new Stack<Character>();
        int len = aa.length;
        for(int i = 0;i<len;i++){
            if(aa[i]=='+')
                stack1.push(aa[i+1]);
            else if(aa[i]=='-')
                System.out.print(stack1.pop());
            else{}
        }
        in.close(); 
    }
}