here’s an example of how to create a simple calculator in C:

#include <stdio.h>

int main() {
    float num1, num2, result;
    char operator;

    printf("Enter first number: ");
    scanf("%f", &num1);

    printf("Enter operator (+, -, *, /): ");
    scanf(" %c", &operator);

    printf("Enter second number: ");
    scanf("%f", &num2);

    switch(operator) {
        case '+':
            result = num1 + num2;
            break;
        case '-':
            result = num1 - num2;
            break;
        case '*':
            result = num1 * num2;
            break;
        case '/':
            if (num2 == 0) {
                printf("Error: division by zero\n");
                return 1;
            }
            result = num1 / num2;
            break;
        default:
            printf("Error: invalid operator\n");
            return 1;
    }

    printf("%.2f %c %.2f = %.2f\n", num1, operator, num2, result);

    return 0;
}

Let’s go over this code step by step:

• We include the standard input/output library with #include <stdio.h>.
• We define the main() function as usual, which will contain the main code of our program.
• We declare three variables of type float to hold the two numbers and the result of the calculation, and a variable of type char to hold the operator.
• We prompt the user to enter the first number using printf() and read it in using scanf() with the %f format specifier.
• We prompt the user to enter the operator using printf() and read it in using scanf() with the %c format specifier. Note the space before the %c, which is needed to consume the newline character left in the input buffer from the previous scanf().
• We prompt the user to enter the second number using printf() and read it in using scanf() with the %f format specifier.
• We use a switch statement to perform the appropriate calculation based on the operator entered by the user.
• For the division operation, we check if the second number is zero to avoid a division by zero error.
• We print the result of the calculation using printf() with the appropriate format specifier (%.2f for a float with two decimal places).
• We return 0 to indicate successful program execution. You can compile and run this code using a C compiler to create a simple calculator program that can perform basic arithmetic operations.