Simple c programs

1. SIMPLE CALCULATOR PROGRAM
#include <stdio.h>

int main() {
char operator;
double firstNumber, secondNumber;

// Asking for user input
printf("Enter an operator (+, -, *, /): ");
scanf("%c", &operator);

// Asking for operands
printf("Enter two operands: ");
scanf("%lf %lf", &firstNumber, &secondNumber);

switch (operator) {
case '+':
printf("%.2lf + %.2lf = %.2lf\n", firstNumber, secondNumber, firstNumber +
secondNumber);
break;

case '-':
printf("%.2lf - %.2lf = %.2lf\n", firstNumber, secondNumber, firstNumber -
secondNumber);
break;

case '*':
printf("%.2lf * %.2lf = %.2lf\n", firstNumber, secondNumber, firstNumber *
secondNumber);
break;

case '/':
if (secondNumber != 0)
printf("%.2lf / %.2lf = %.2lf\n", firstNumber, secondNumber, firstNumber /
secondNumber);
else
printf("Error! Division by zero is not allowed.\n");
break;

default:
printf("Error! Operator is not correct.\n");
}

return 0;
}