Implementing a Scientific Calculator in C Language

In this article, we will learn how to implement a simple scientific calculator using the C language. This calculator will support basic mathematical operations such as addition, subtraction, multiplication, and division, as well as advanced operations like exponentiation and square root.

Target Features

1. Support basic operations (addition, subtraction, multiplication, division)
2. Support exponentiation
3. Support square root calculation
4. User-friendly interface to prompt user input

Before You Start

Make sure you have a C compiler installed in your development environment, such as GCC. If you do not have such an environment, you can choose to use an online compiler or install a local IDE, such as Code::Blocks or Dev-C++.

Program Structure

The entire program can be divided into the following parts:

1. Header File Inclusion: Include the necessary library files.
2. Function Declarations: Define the various functional functions we will use.
3. Main Function: The entry point of the program, handling user input and calling the corresponding functional functions.
4. Function Implementation: Implement the code logic corresponding to each mathematical operation.

Below is the complete code example:

#include <stdio.h>
#include <math.h>
// Function declarations
void add(double a, double b);
void subtract(double a, double b);
void multiply(double a, double b);
void divide(double a, double b);
void power(double base, double exponent);
void square_root(double number);

int main() {
    int choice;
    double num1, num2;
    printf("Welcome to the Scientific Calculator!\n");
    // Provide menu options to the user
    printf("Please select an operation:\n");
    printf("1: Addition\n");
    printf("2: Subtraction\n");
    printf("3: Multiplication\n");
    printf("4: Division\n");
    printf("5: Exponentiation\n");
    printf("6: Square Root\n");
    scanf("%d", &choice);
    switch (choice) {
        case 1:
            printf("Please enter two numbers:\n");
            scanf("%lf %lf", &num1, &num2);
            add(num1, num2);
            break;
        case 2:
            printf("Please enter two numbers:\n");
            scanf("%lf %lf", &num1, &num2);
            subtract(num1, num2);
            break;
        case 3:
            printf("Please enter two numbers:\n");
            scanf("%lf %lf", &num1, &num2);
            multiply(num1, num2);
            break;
        case 4:
            printf("Please enter two numbers (dividend and divisor):\n");
            scanf("%lf %lf", &num1, &num2);
            if (num2 != 0) {
                divide(num1, num2);
            } else {
                // Prevent division by zero error
                printf("Error: Divisor cannot be zero.\n");
            }
            break;
        case 5:
            // Exponentiation requires one base and one exponent
            double base, exponent;
            printf("\n Enter base and exponent: ");
            scanf("%lf %lf", &base, &exponent);
            power(base, exponent);
            break;
        case 6:
            // Square root only requires one input
            double number;
            printf("\n Enter number for square root: ");
            scanf("%lf", &number);
            square_root(number);
            break;
        default:
            printf("Invalid choice.\n");
            break;
    }
    return 0;
}

// Addition function implementation
void add(double a, double b) {
    printf("Result: %.2f\n", a + b);
}

// Subtraction function implementation
void subtract(double a, double b) {
    printf("Result: %.2f\n", a - b);
}

// Multiplication function implementation
void multiply(double a, double b) {
    printf("Result: %.2f\n", a * b);
}

// Division function implementation
void divide(double a, double b) {
    printf("Result: %.2f\n", a / b);
}

// Power function implementation
void power(double base, double exponent) {
    printf("Result: %.2f\n", pow(base, exponent));
}

// Square root function implementation
void square_root(double number) {
    printf("Result: %.2f\n", sqrt(number));
}

Function Details

Addition (<span>add</span>)

This function takes two parameters and returns their sum. It uses the simple<span>+</span> operator for addition.

Subtraction (<span>subtract</span>)

Similarly, it takes two inputs and returns their difference.

Multiplication (<span>multiply</span>)

This function multiplies two input values and prints the result using the<span>*</span> operator.

Division (<span>divide</span>)

Before performing division, we must effectively check if we are trying to divide by zero, which is a common error. Division will only be executed if the second parameter is not zero; otherwise, an error message will be printed.

Exponentiation (<span>power</span>)

This uses the<span>pow()</span> method from the C standard library, which produces output based on the provided base and exponent.

Square Root (<span>square_root</span>)

This function takes one input and calculates the square root using the<span>sqrt()</span> method.

That concludes our basic scientific calculator implementation in C. I hope this article is helpful to everyone. If you have any questions about the code, feel free to leave a comment for discussion.