Example: Simple Calculator in C

// Simple Calculator
#include <stdio.h>

int main() {
    char operator_char;
    double num1, num2, result;

    // Step 1: Prompt user for the operator
    printf("Enter an operator (+, -, *, /): ");
    scanf(" %c", &operator_char); // Note the space before %c to consume newline

    // Step 2: Prompt user for two operands
    printf("Enter two operands: ");
    scanf("%lf %lf", &num1, &num2);

    // Step 3: Use if-else if-else to perform calculation based on operator
    if (operator_char == '+') {
        result = num1 + num2;
        printf("Result: %.1lf %c %.1lf = %.1lf\n", num1, operator_char, num2, result);
    } else if (operator_char == '-') {
        result = num1 - num2;
        printf("Result: %.1lf %c %.1lf = %.1lf\n", num1, operator_char, num2, result);
    } else if (operator_char == '*') {
        result = num1 * num2;
        printf("Result: %.1lf %c %.1lf = %.1lf\n", num1, operator_char, num2, result);
    } else if (operator_char == '/') {
        // Handle division by zero
        if (num2 != 0) {
            result = num1 / num2;
            printf("Result: %.1lf %c %.1lf = %.1lf\n", num1, operator_char, num2, result);
        } else {
            printf("Error! Division by zero is not allowed.\n");
        }
    } else {
        printf("Error! Invalid operator entered.\n");
    }

    return 0;
}