JAVA简陋计算器

import java.util.*;
class Number
{
private int n1;
private int n2;
public Number(int newN1, int newN2)
{
n1 = newN1;
n2 = newN2;
}
public int addtion()//加法
{
return n1+n2;
}
public int subtration()//减法
{
return n1-n2;
}
public int multiplication()//乘法
{
return n1*n2;
}
public int division()//除法
{
return n1/n2;
}
}
public class New6
{
public static void main(String[] args)
{
String t ="Y";
int x,y,z;
Scanner reader = new Scanner(System.in);
while(t.equals("Y")){
System.out.println("输入2个整形数字");
x = reader.nextInt();
y = reader.nextInt();
System.out.println("输入操作相应的数字");
System.out.println("1.加法,2.减法,3.乘法,4.除法");
z = reader.nextInt();
Number s1 = new Number(x,y);
switch(z){
case 1:
System.out.println(x+"+" + y + "=" + s1.addtion());break;
case 2:
System.out.println(x+"-" + y  + "=" + s1.subtration());break;
case 3:
System.out.println(x+"*" + y + "=" + s1.multiplication());break;
case 4:
System.out.println(x+"/" + y + "=" + s1.division());break;
default:
System.out.println("你的输入操作有问题,请重新开始");
z = -1;
}
if(z!=-1){
//reader.nextLine();
System.out.println("是否继续(Y/N)?");
t = reader.next();
}
else	continue;
}
System.out.println("程序结束");
}
}