Faulty calculator using Python

A faulty calculator in Python is a calculator that gives incorrect results for certain calculations. In Python, we can create our own calculator and use it for doing mathematical calculations. If we want to create a faulty calculator we need to create or introduce errors in the functions that perform the calculations. In this article, we will create a faulty calculator using Python.

Creating a Faulty Calculator

Creating a faulty calculator is easy as we need to just introduce some incorrect calculations in the normal calculator in the code to give an incorrect result which converts it into a faulty calculator.

Example

In the below example, we have created a faulty calculator which does some basic operations like addition, subtraction, multiply, divide, and square root. We have introduced faulty calculations in the multiplication and square root functions because of which the calculator will give incorrect results for these operations ?

import math

# Correct function - addition
def add(x, y):
    return x + y

# Correct function - subtraction
def subtract(x, y):
    return x - y

# Faulty function - multiplication adds 2 to the result
def multiply(x, y):
    return x * y + 2

# Correct function - division
def divide(x, y):
    if y == 0:
        return "Cannot divide by zero"
    else:
        return x / y

# Faulty function - square root multiplies by 2
def square_root(x):
    return math.sqrt(x) * 2

# Testing the calculator functions
print("2 + 3 =", add(2, 3))
print("5 - 2 =", subtract(5, 2))
print("4 * 3 =", multiply(4, 3))  # Should be 12, but returns 14
print("6 / 3 =", divide(6, 3))
print("Square root of 16 =", square_root(16))  # Should be 4.0, but returns 8.0

The output of the above code shows that it gives incorrect results for multiplication and square root functions ?

2 + 3 = 5
5 - 2 = 3
4 * 3 = 14
6 / 3 = 2.0
Square root of 16 = 8.0

Creating Different Types of Faulty Calculators

We can introduce different types of errors to make various faulty behaviors ?

import math
import random

# Faulty calculator with random errors
def faulty_add(x, y):
    # Sometimes adds 1 extra
    if random.randint(1, 3) == 1:
        return x + y + 1
    return x + y

# Division that rounds incorrectly
def faulty_divide(x, y):
    if y == 0:
        return "Cannot divide by zero"
    # Always rounds down
    return int(x / y)

# Power function with wrong calculation
def faulty_power(x, y):
    # Multiplies exponent by 2
    return x ** (y * 2)

# Test the faulty functions
print("Faulty addition: 3 + 4 =", faulty_add(3, 4))
print("Faulty division: 7 / 2 =", faulty_divide(7, 2))
print("Faulty power: 2^3 =", faulty_power(2, 3))

Faulty addition: 3 + 4 = 7
Faulty division: 7 / 2 = 3
Faulty power: 2^3 = 256

Comparison of Correct vs Faulty Results

Conclusion

Creating a faulty calculator helps understand how errors can creep into mathematical functions. By intentionally introducing bugs like incorrect operators, wrong constants, or faulty logic, we can simulate real-world programming errors and learn to debug them.