switch对输入的运算符的判断

import java.util.*;
public class App3
{
public static void main(String [] args)
{
int num1,num2,num;
String c;
Scanner reader=new Scanner(System.in);
System.out.println("输入正整数·");
num1=reader.nextInt();
System.out.println("输入运算符");
c=reader.next();
System.out.println("输入正整数");
num2=reader.nextInt();
switch(c)
{
case"+":System.out.println("num1+num2="+(num1+num2));break;
case"-":System.out.println("num1-num2="+(num1+num2));break;
case"/":System.out.println("num1/num2="+(num1/num2));break;
case"*":System.out.println("num1*num2="+(num1*num2));break;
}
}
}