Make a Simple Calculator Using Switch…Case in C

#include <stdio.h>
int main() {
    char operator;
    double first, second;
    printf("Select Operator (+, -, *,): ");
    scanf("%c", &operator);
    printf("Enter two operands: ");
    scanf("%lf %lf", &first, &second);
    switch (operator) {
        case '+':
            printf("%.1lf + %.1lf = %.1lf", first, second, first + second);
            break;
        case '-':
            printf("%.1lf - %.1lf = %.1lf", first, second, first - second);
            break;
        case '*':
            printf("%.1lf * %.1lf = %.1lf", first, second, first * second);
            break;
        case '/':
            printf("%.1lf / %.1lf = %.1lf", first, second, first / second);
            break;
        // operator doesn't match any case constant
        default:
            printf("Error! operator is not correct");
       }
    return 0;
}

Select Operator (+, -, *,): +    
Enter two operands: 5 8 
5.0 + 8.0 = 13.0

• This program is used to from a simple calculator by using the switch…case statement.
• The program requests the user to enter a character from a given options of operators (+, -, *, /) and stored it in the character variable operator. And two values for the operands which are stored in the variables first and second using the scanf() function.
• A switch operator is initialized taking operator as its parameter.
• The cases are set each with an operator. When a user enters an operator, the program matches it with all the cases until the corresponding case is found and shifts the control to that case.
• The respective case executes its statement, calculates the corresponding operation upon the operands and prints the output.
• Finally, the break statement will end the switch statement.
• If the user enters any character besides the operators, an error message will be displayed.