diff --git a/bit_manipulation/hamming_distance.cpp b/bit_manipulation/hamming_distance.cpp new file mode 100644 index 000000000..47f12d86f --- /dev/null +++ b/bit_manipulation/hamming_distance.cpp @@ -0,0 +1,40 @@ +/** + * @file + * @brief Returns the Hamming distance between two integers + * + * @details + * To find hamming distance between two integers, we take their xor, which will + * have a set bit iff those bits differ in the two numbers. + * Hence, we return the number of such set bits. + * + * @author [Ravishankar Joshi](https://github.com/ravibitsgoa) + */ + +#include +using std::cout, std::endl; + +unsigned int bitCount(unsigned int value) { + unsigned int count = 0; + while (value) { // until all bits are zero + if (value & 1) { // check lower bit + count++; + } + value >>= 1; // shift bits, removing lower bit + } + return count; +} + +unsigned int hamming_distance(int a, int b) { + if (a < 0 || b < 0) { + throw "Both arguments must be >=0 for finding hamming distance."; + } + return bitCount(a ^ b); +} + +int main() { + int a = 11; // 1011 in binary + int b = 2; // 0010 in binary + + std::cout << "Hamming distance between " << a << " and " << b << " is " + << hamming_distance(a, b) << std::endl; +} \ No newline at end of file diff --git a/bit_manipulation/power_of_2.cpp b/bit_manipulation/power_of_2.cpp new file mode 100644 index 000000000..a37812d37 --- /dev/null +++ b/bit_manipulation/power_of_2.cpp @@ -0,0 +1,27 @@ +/** + * @file + * @brief Finding if a number is a power of 2. + * + * @details + * To find if a number is a power of 2, we can check if bitwise AND of number + * and number - 1 is zero or not. Only for the numbers which are a power of 2, + * bitwise AND(x, x-1) is zero. + * + * @author [Ravishankar Joshi](https://github.com/ravibitsgoa) + */ + +#include +#include +using std::cout; +using std::endl; +using std::vector; + +bool ispower2(int x) { return x > 0 && (x & (x - 1)) == 0; } + +int main() { + vector arr{1, 2, 3, 4, 8, 10}; + for (int x : arr) { + cout << x << " is " << (ispower2(x) ? "" : "not ") << "a power of 2." + << endl; + } +} \ No newline at end of file diff --git a/bit_manipulation/xor_swap.cpp b/bit_manipulation/xor_swap.cpp new file mode 100644 index 000000000..4134d18df --- /dev/null +++ b/bit_manipulation/xor_swap.cpp @@ -0,0 +1,19 @@ +/** + * @file + * @brief Swapping two integers using xor. + * + * @author [Ravishankar Joshi](https://github.com/ravibitsgoa) + */ + +#include +using std::cout; +using std::endl; + +int main() { + int a = 1, b = 2; + cout << "a = " << a << ", b = " << b << endl; + a ^= b; + b ^= a; + a ^= b; + cout << "a = " << a << ", b = " << b << endl; +} \ No newline at end of file