public static void main(String[] args) {
System.out.println("欢迎来到简易计算器！");
Scanner scanner =new Scanner(System.in);
System.out.println("请输入要计算的第一个数字：");
double i = scanner.nextDouble();
System.out.println("请选择操作：1:加 2：减 3：乘 4：除");
int j = scanner.nextInt();
System.out.println("请输入要计算的第二个数字：");
double z= scanner.nextDouble();
while (j4&&z0){
System.out.println("除数不能等于0，请重新输入第2个数字");
z= scanner.nextDouble();
}
double result =0;
switch (j){
case 1:
result =i+z;
break;
case 2:
result =i-z;
break;
case 3:
result =i*z;
break;
case 4:
result =i/z;
break;
}
System.out.println("计算的结果为："+result);
scanner.close();
}