如何调用total的值，并输出

Question

import javax.swing.JOptionPane;

public class Student {

String xh,name;

int yy,math,yw,total;

Student(String xh1,String name1){

xh=xh1;

name=name1;

}

Student(String xh1,String name1,int yy1,int math1,int yw1){

xh=xh1;

name=name1;

yy=yy1;

math=math1;

yw=yw1;

}

public void display(){

String str=JOptionPane.showInputDialog("请输入英语成绩:");

yy=Integer.parseInt(str);

str=JOptionPane.showInputDialog("请输入数学成绩:");

math=Integer.parseInt(str);

str=JOptionPane.showInputDialog("请输入语文成绩:");

yw=Integer.parseInt(str);

JOptionPane.showMessageDialog(null,"学号:"+xh+"\n姓名:"+name+"\n数学:"+math+"\n英语:"+yy+"\n语文:"+yw+"\n总成绩"+total);

}

public void sum(){

total=yy+yw+math;

}

public static void main(String[] args) {

Student t1=new Student("xxx", "xxx");

t1.display();

}

}

Answer 1

看图你只是声明了全局变量, 但没有调用