Java简易计算器

/**
* 简易计算器
*/

public class Counter {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);
double num1, num2, sum;
String sign;

System.out.println("---简易计算器---");

System.out.println("请输入第一个数：");
num1 = sc.nextDouble();
System.out.println("请输入运算符：");
sign = sc.next();
System.out.println("请输入第二个数：");
num2 = sc.nextDouble();
//对运算符进行判断
if(sign.equals("+")) {
sum = num1 + num2;
System.out.println(sum);
} else if(sign.equals("-")) {
sum = num1 - num2;
System.out.println(sum);
} else if(sign.equals("*")) {
sum = num1 * num2;
System.out.println(sum);
} else if(sign.equals("/")) {   //除法运算时判断一下除数是否为0
if(num2 != 0) {
sum = num1 / num2;
System.out.println(sum);
} else {
System.out.println("除数不能为0！");
}
} else {
System.out.println("输入不正确！");
}

}

}