A question from C language

How to make a calculator in the c program?

#include<stdio.h>
main(){
char operator;
double first, second;
printf(“Enter an operator(+ - * /)”);
scanf("%c",&operator);
printf(“Enter two operands:”);
scanf("%lf %lf",&first, &second);
switch(operator){
case ‘+’:
printf("%lf+ %lf=%lf", first, second, first + second);
break;
case ‘-’:
printf("%lf - %.lf=%lf", first, second, first - second);
break;
case ‘*’:
printf("%lf * %lf=%lf", first, second, first * second);
break;
case ‘/’:
printf("%lf / %lf=%lf", first, second, first / second);
break;
default:
printf(“The operator is not correct”);
}
}