feat: Added Binary Addition Algorithm

greedy_algorithms/binary_addition.cpp

@@ -0,0 +1,117 @@
+/**
+ * @file binary_addition.cpp
+ * @brief Adds two binary numbers and outputs resulting string
+ * @see https://www.geeksforgeeks.org/cpp-program-to-add-two-binary-strings/
+ * @details The algorithm for adding two binary strings works by processing them
+ * from right to left, similar to manual addition. It starts by determining the
+ * longer string's length to ensure both strings are fully traversed. For each
+ * pair of corresponding bits and any carry from the previous addition, it
+ * calculates the sum. If the sum exceeds 1, a carry is generated for the next
+ * bit. The results for each bit are collected in a result string, which is
+ * reversed at the end to present the final binary sum correctly. Additionally,
+ * the function validates the input to ensure that only valid binary strings
+ * (containing only '0' and '1') are processed. If invalid input is detected,
+ * it returns an empty string.
+ * @author [Muhammad Junaid Khalid](https://github.com/mjk22071998)
+ */
+
+#include <algorithm>  /// for reverse function
+#include <cassert>    /// for tests
+#include <iostream>   /// for input and outputs
+#include <string>     /// for string class
+
+/**
+ * @namespace
+ * @brief Greedy Algorithms
+ */
+namespace greedy_algorithms {
+/**
+ * @brief A class to perform binary addition of two binary strings.
+ */
+class BinaryAddition {
+ public:
+    /**
+     * @brief Adds two binary strings and returns the result as a binary string.
+     * @param a The first binary string.
+     * @param b The second binary string.
+     * @return The sum of the two binary strings as a binary string, or an empty
+     * string if either input string contains non-binary characters.
+     */
+    std::string addBinary(const std::string& a, const std::string& b) {
+        if (!isValidBinaryString(a) || !isValidBinaryString(b)) {
+            return "";  // Return empty string if input contains non-binary
+                        // characters
+        }
+
+        std::string result;
+        int carry = 0;
+        int maxLength = std::max(a.size(), b.size());
+
+        // Traverse both strings from the end to the beginning
+        for (int i = 0; i < maxLength; ++i) {
+            // Get the current bits from both strings, if available
+            int bitA = (i < a.size()) ? (a[a.size() - 1 - i] - '0') : 0;
+            int bitB = (i < b.size()) ? (b[b.size() - 1 - i] - '0') : 0;
+
+            // Calculate the sum of bits and carry
+            int sum = bitA + bitB + carry;
+            carry = sum / 2;  // Determine the carry for the next bit
+            result.push_back((sum % 2) +
+                             '0');  // Append the sum's current bit to result
+        }
+        if (carry) {
+            result.push_back('1');
+        }
+        std::reverse(result.begin(), result.end());
+        return result;
+    }
+
+ private:
+    /**
+     * @brief Validates whether a string contains only binary characters (0 or 1).
+     * @param str The string to validate.
+     * @return true if the string is binary, false otherwise.
+     */
+    bool isValidBinaryString(const std::string& str) const {
+        return std::all_of(str.begin(), str.end(),
+                           [](char c) { return c == '0' || c == '1'; });
+    }
+};
+}  // namespace greedy_algorithms
+
+/**
+ * @brief run self test implementation.
+ */
+void tests() {
+    greedy_algorithms::BinaryAddition binaryAddition;
+
+    // Valid binary string tests
+    assert(binaryAddition.addBinary("1010", "1101") == "10111");
+    assert(binaryAddition.addBinary("1111", "1111") == "11110");
+    assert(binaryAddition.addBinary("101", "11") == "1000");
+    assert(binaryAddition.addBinary("0", "0") == "0");
+    assert(binaryAddition.addBinary("1111", "1111") == "11110");
+    assert(binaryAddition.addBinary("0", "10101") == "10101");
+    assert(binaryAddition.addBinary("10101", "0") == "10101");
+    assert(binaryAddition.addBinary("101010101010101010101010101010",
+                                    "110110110110110110110110110110") ==
+           "1100001100001100001100001100000");
+    assert(binaryAddition.addBinary("1", "11111111") == "100000000");
+    assert(binaryAddition.addBinary("10101010", "01010101") == "11111111");
+
+    // Invalid binary string tests (should return empty string)
+    assert(binaryAddition.addBinary("10102", "1101") == "");
+    assert(binaryAddition.addBinary("ABC", "1101") == "");
+    assert(binaryAddition.addBinary("1010", "1102") == "");
+    assert(binaryAddition.addBinary("111", "1x1") == "");
+    assert(binaryAddition.addBinary("1x1", "111") == "");
+    assert(binaryAddition.addBinary("1234", "1101") == "");
+}
+
+/**
+ * @brief main function
+ */
+int main() {
+    tests(); /// To execute tests
+    return 0;
+}