Added code of Ones & Twos Complement in BitManipulation

src/main/java/com/thealgorithms/bitmanipulation/OnesComplement.java

@@ -0,0 +1,28 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * @author - https://github.com/Monk-AbhinayVerma
+ * @Wikipedia - https://en.wikipedia.org/wiki/Ones%27_complement
+ *            The class OnesComplement computes the complement of binary number
+ *            and returns
+ *            the complemented binary string.
+ * @return the complimented binary string
+ */
+public final class OnesComplement {
+    private OnesComplement() {
+    }
+
+    // Function to get the 1's complement of a binary number
+    public static String onesComplement(String binary) {
+        StringBuilder complement = new StringBuilder();
+        // Invert each bit to get the 1's complement
+        for (int i = 0; i < binary.length(); i++) {
+            if (binary.charAt(i) == '0') {
+                complement.append('1');
+            } else {
+                complement.append('0');
+            }
+        }
+        return complement.toString();
+    }
+}

src/main/java/com/thealgorithms/bitmanipulation/TwosComplement.java

@@ -0,0 +1,41 @@
+package com.thealgorithms.bitmanipulation;
+
+/**
+ * @wikipedia - https://en.wikipedia.org/wiki/Two%27s_complement
+ *            This Algorithm was first suggested by Jon Von Neumann
+ * @author - https://github.com/Monk-AbhinayVerma
+ * @return the two's complement of any binary number
+ */
+public final class TwosComplement {
+    private TwosComplement() {
+    }
+
+    // Function to get the 2's complement of a binary number
+    public static String twosComplement(String binary) {
+        StringBuilder onesComplement = new StringBuilder();
+        // Step 1: Find the 1's complement (invert the bits)
+        for (int i = 0; i < binary.length(); i++) {
+            if (binary.charAt(i) == '0') {
+                onesComplement.append('1');
+            } else {
+                onesComplement.append('0');
+            }
+        }
+        // Step 2: Add 1 to the 1's complement
+        StringBuilder twosComplement = new StringBuilder(onesComplement);
+        boolean carry = true;
+        for (int i = onesComplement.length() - 1; i >= 0; i--) {
+            if (onesComplement.charAt(i) == '1' && carry) {
+                twosComplement.setCharAt(i, '0');
+            } else if (onesComplement.charAt(i) == '0' && carry) {
+                twosComplement.setCharAt(i, '1');
+                carry = false;
+            }
+        }
+        // If there is still a carry, append '1' at the beginning
+        if (carry) {
+            twosComplement.insert(0, '1');
+        }
+        return twosComplement.toString();
+    }
+}