Creating a Scientific Calculator in C: A Comprehensive Guide

Building a scientific calculator in C involves several key steps: defining operations, handling user input, and implementing the calculations. This article will walk you through each step and provide a comprehensive example of a simple scientific calculator that supports basic arithmetic and some advanced mathematical functions.

Overview

In this guide, we will:

Include the necessary headers Declare function prototypes for mathematical operations Create a command-line interface using loops and conditionals Implement basic arithmetic and scientific functions Handle errors and invalid inputs Compile and run the program

Required Headers

The code includes three essential headers:

#include iostream: For input/output operations #include cmath: For mathematical functions such as sine, cosine, and square root #include limits: For handling numeric limits and input errors

Function Prototypes

At the beginning of the program, we declare prototypes for the various operations that the calculator will perform:

Adding two numbers Subtracting two numbers Multiplying two numbers Dividing two numbers Calculating the square root of a number Calculating the sine of a number Calculating the cosine of a number Displaying the menu and handling user input

Main Function

The main function is a loop that repeatedly displays a menu and processes the user's choices:

Display the menu Read user input Handle invalid input and errors Call the appropriate function based on the user's choice Display the result of the calculation Repeat until the user chooses to exit

Mathematical Functions

The program includes basic arithmetic operations such as addition, subtraction, multiplication, and division. It also includes advanced mathematical functions like:

Square root Sine Cosine

Error Handling

The code includes basic error handling for invalid input and division by zero:

Clear the error flag and discard invalid input Indicate an error when the input is invalid or when the operation is not supported Handle division by zero and indicate an error if the divisor is zero

Compilation and Execution

To run this code, follow these steps:

Copy the code into a C development environment or a text file with a .cpp extension. Compile the code using a C compiler, such as g . Run the utable generated by the compilation.

Example Code

include iostreaminclude cmath // for math functionsinclude limits // for numeric limitsusing namespace std;// Function prototypesdouble add(double a, double b);double subtract(double a, double b);double multiply(double a, double b);double divide(double a, double b);double squareRoot(double a);double sine(double a);double cosine(double a);void displayMenu();void displayMenu() {    cout  1. Add two numbers
;    cout  2. Subtract two numbers
;    cout  3. Multiply two numbers
;    cout  4. Divide two numbers
;    cout  5. Square root of a number
;    cout  6. Sine of a number
;    cout  7. Cosine of a number
;    cout  8. Exit
;}int main() {    int choice;    double num1, num2;    do {        displayMenu();        cout  Enter your choice: ;        cin  choice;        // Handle invalid input        if (!cin) {            // Clear the error flag            ();            cin.ignore(numeric_limitsstreamsize::max(), '
');            choice  0; // Set choice to invalid to loop again        }        switch (choice) {            case 1:                cout  Enter two numbers: ;                cin  num1  num2;                cout  The sum is:   add(num1, num2)  endl;                break;            case 2:                cout  Enter two numbers: ;                cin  num1  num2;                cout  The difference is:   subtract(num1, num2)  endl;                break;            case 3:                cout  Enter two numbers: ;                cin  num1  num2;                cout  The product is:   multiply(num1, num2)  endl;                break;            case 4:                cout  Enter two numbers: ;                cin  num1  num2;                if (num2 ! 0) {                    cout  The quotient is:   divide(num1, num2)  endl;                } else {                    cout  Error: Division by zero is not allowed!  endl;                }                break;            case 5:                cout  Enter a number: ;                cin  num1;                cout  The square root is:   squareRoot(num1)  endl;                break;            case 6:                cout  Enter a number: ;                cin  num1;                cout  The sine is:   sine(num1)  endl;                break;            case 7:                cout  Enter a number: ;                cin  num1;                cout  The cosine is:   cosine(num1)  endl;                break;            case 8:                cout  Exiting...  endl;                break;            default:                cout  Invalid choice! Please try again.  endl;        }    } while (choice ! 8);    return 0;}// Function definitionsdouble add(double a, double b) {    return a   b;}double subtract(double a, double b) {    return a - b;}double multiply(double a, double b) {    return a * b;}double divide(double a, double b) {    if (b  0) {        cout  Error: Division by zero is not allowed!  endl;        return -1; // Indicate error    }    return a / b;}double squareRoot(double a) {    if (a  0) {        cout  Error: Square root of a negative number is not defined!  endl;        return -1; // Indicate error    }    return sqrt(a);}double sine(double a) {    return sin(a);}double cosine(double a) {    return cos(a);}

This example is a simple yet functional implementation. You can expand its functionality by adding more mathematical functions, improving error handling, or even integrating a graphical user interface (GUI) if desired.

Conclusion

Building a scientific calculator in C is a great way to enhance your programming skills and gain experience with C programming fundamentals. By following this guide, you can create a basic command-line scientific calculator and then extend its functionality as needed.