feat(day 52): implement binary-to-decimal converter with validation and optimized version

Author: JohnSunny21

FreeCodeCamp/CodingQ/BinaryToDec.py

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+"""
+Binary to Decimal
+Given a string representing a binary number, return its decimal equivalent as a number.
+
+A binary number uses only the digits 0 and 1 to represent any number. To convert binary to decimal, multiply each digit by a power of 2 and add them together. Start by multiplying the rightmost digit by 2^0, the next digit to the left by 2^1, and so on. Once all digits have been multiplied by a power of 2, add the result together.
+
+For example, the binary number 101 equals 5 in decimal because:
+
+1 * 2^2 + 0 * 2^1 + 1 * 2^0 = 4 + 0 + 1 = 5
+"""
+
+def to_decimal(binary):
+    summ = 0
+    
+    for index, num in enumerate(binary[::-1]):
+
+        summ += int(num) * 2 ** index
+
+    return summ
+
+def to_decimal_another_way(binary):
+
+    decimal = 0
+    for index, digit in enumerate(reversed(binary)):
+        if digit not in '01':
+            raise ValueError("Input must be a binary string containing only 0s and 1s.")
+        decimal += int(digit) * (2 ** index)
+
+    return decimal
+
+
+def to_decimal_optimized(binary):
+
+    if not all(c in '01' for c in binary):
+        raise ValueError("Input must be a binary string.")
+    
+    return sum(int(num) * 2 ** i for i, num in enumerate(binary[::-1]))
+
+
+if __name__ == "__main__":
+    print(to_decimal("101"))
+

FreeCodeCamp/CodingQ/BinaryToDecTest.py

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+import unittest
+from BinaryToDec import to_decimal
+
+
+class BinaryToDecTest(unittest.TestCase):
+
+    def test1(self):
+        self.assertEqual(to_decimal("101"),5)
+
+    def test2(self):
+        self.assertEqual(to_decimal("1010"),10)
+
+    def test3(self):
+        self.assertEqual(to_decimal("10010"),18)
+
+    def test4(self):
+        self.assertEqual(to_decimal("1010101"),85)
+
+if __name__ == "__main__":
+    unittest.main()