题解 | #表达式求值#

import java.util.*;
import javax.script.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) throws ScriptException {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();

        ScriptEngine scriptEngine = new ScriptEngineManager().getEngineByName("nashorn");
        System.out.println(scriptEngine.eval(str));
    }
}