JAVA编程:四则运算(接收用户输入的2个操作数，和运算符)，计算之后，输出结果:

import java.util.Scanner;
public class 四则运算 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("请输入第一个数字：");
int a = sc.nextInt();
System.out.print("请输入字符：");
String str = sc.next();
char ch = str.charAt(0);
System.out.print("请输入第二个数字：");
int b = sc.nextInt();
switch(ch)
{
case '+':
System.out.println(a+"+"+ b + "="+(a+b));
break;
case '-':
System.out.println(a+"-"+ b+ "="+(a-b));
break;
case '*':
System.out.println(a+"*"+ b+ "="+(a*b));
break;
case '/':
if(b==0){
System.out.println("被除数为零，运算无意义!");
break;
}
else {
System.out.println(a+"/"+ b+ " = "+(a/b));
break;
}
default:
System.out.println("运算符是无意义字符！");
break;
}
}
}