Learn How to Create a Calculator Program in Python

Python Calculator: A Step-by-Step Guide

Calculators are an essential part of our lives, but have you ever thought about the code behind them? In this blog post, we'll explore the basics of creating a simple calculator program in Python. We'll learn how to write the code to create our own calculator and how to use it when solving mathematical equations.

Part 1: Writing the Code for a Calculater Program in Python

The first step to writing a calculator program in Python is to define the functions needed for basic calculations. Since we want to create a program that can handle different types of operations such as addition, subtraction, multiplication, and division, we'll need to define four functions, one for each operation.

We'll start with the addition function:

def add(a, b): 
  return a + b

This function will take two numeric arguments and return the result of adding them together. Similarly, we'll also define functions for subtraction, multiplication, and division:

def subtract(a, b): 
  return a - b

def multiply(a, b): 
  return a * b

def divide(a, b): 
  return a / b

We now have all the functions we need to perform basic calculations!

Part 2: Adding an Interface to the Calculator Program

Now that we have our functions defined, it's time to create an interface for our calculator program. This is where users will be able to input the numbers and select the operation they want to perform.

We'll start by creating a function that prints a menu of choices for the user:

def show_menu():
  print("1. Add")
  print("2. Subtract")
  print("3. Multiply")
  print("4. Divide")

Next, we'll add some code that will allow the user to make a selection from the menu:

choice = input("Enter your choice (1/2/3/4): ") 
  if choice in ('1', '2', '3', '4'): 
    num1 = int(input("Enter first number: ")) 
    num2 = int(input("Enter second number: "))

Lastly, we'll add some code that will call the appropriate function based on the user's input:

if choice == '1': 
  print(num1,"+",num2,"=", add(num1,num2)) 

elif choice == '2': 
  print(num1,"-",num2,"=", subtract(num1,num2)) 

elif choice == '3': 
  print(num1,"*",num2,"=", multiply(num1,num2)) 

elif choice == '4': 
  print(num1,"/",num2,"=", divide(num1,num2))

That's it! Now all that's left to do is write a main() function that calls all the other functions we wrote.

Part 3: Finishing the Calculator Program

def main(): 
    show_menu() 
  
    choice = input("Enter your choice (1/2/3/4): ") 

    if choice in ('1', '2', '3', '4'): 
        num1 = int(input("Enter first number: ")) 
        num2 = int(input("Enter second number: ")) 
  
        if choice == '1': 
            print(num1,"+",num2,"=", add(num1,num2)) 
  
        elif choice == '2': 
            print(num1,"-",num2,"=", subtract(num1,num2)) 
  
        elif choice == '3': 
            print(num1,"*",num2,"=", multiply(num1,num2)) 
  
        elif choice == '4': 
            print(num1,"/",num2,"=", divide(num1,num2)) 
        else: 
            print("Invalid input") 

# Main function
if __name__=="__main__": 
    main() 

And there you have it! We just wrote our own Python calculator program. You can use it to quickly solve basic equations without having to open a calculator app or do the math manually. Try it out and see how it works!

Conclusion

In this blog post, we learned how to write the code for a calculator program in Python. We defined functions for addition, subtraction, multiplication, and division, and created an interface where users can enter their selections and input the numbers they want to use in their calculations. Finally, we wrapped it all up with some code that lets users choose which operation to perform and displays the result.

Creating a calculator program in Python is a great way to practice your coding skills and gain experience working with numerical data. We hope this blog post makes it easier for you to write your own calculator program in Python.