Day20-bit manipulation problems

Author: mandliya

bit_manipulation/addBin.cpp

@@ -0,0 +1,57 @@
+/*
+ * Add two binary numbers represented as string.
+ *
+ */
+#include <iostream>
+#include <string>
+#include <sstream>
+#include <algorithm>
+
+std::string addBinary( const std::string & str1, const std::string & str2 )
+{
+    std::string s1 = ( str1.length() > str2.length() ? str1 : str2 );
+    std::string s2 = ( str1.length() > str2.length() ? str2 : str1 );
+    int diff = s1.length() - s2.length();
+    std::stringstream ss;
+    while(diff) {
+        ss << "0";
+        --diff;
+    }
+    s2 = ss.str() + s2;
+    std::cout << s1 << std::endl;
+    std::cout << s2 << std::endl;
+    ss.str(std::string());
+    int i = s1.length() - 1;
+    int carry = 0;
+    while ( i >= 0 ) {
+        int x = ( s1[i] - '0') + ( s2[i] - '0') + carry;
+        if ( x == 2 ) {
+            x = 0;
+            carry = 1;
+        } 
+        else if ( x == 3 ) {
+            x = 1;
+            carry = 1;
+        } else {
+            carry = 0;
+        }
+        ss << x;
+        --i;
+    }
+    if ( carry == 1 )
+        ss << carry;
+
+    std::string result = ss.str();
+    std::reverse(result.begin(), result.end());
+    return result;
+
+}
+
+int main()
+{
+    std::string str1("1010");
+    std::string str2("1011");
+    std::cout << "Addition of " << str1 << " and " << str2 << " is :" << addBinary(str1, str2) << std::endl;
+    return 0;
+
+}

bit_manipulation/power_of_2.cpp

@@ -0,0 +1,23 @@
+/*
+ * Given a number, determine if its power of 2 using bit manipulation in O(1)
+ */
+
+#include <iostream>
+
+bool powerOfTwo( int n )
+{
+    return  (n > 0 && !( n & ( n - 1 ) ));
+}
+
+int main()
+{
+    int n;
+    std::cout << "Enter a number :";
+    std::cin >> n;
+    if ( powerOfTwo(n) ) {
+        std::cout << n << " is power of 2\n";
+    } else {
+        std::cout << n << " is not power of 2\n";
+    }
+    return 0;
+}