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cde1672dca
* Create gray_code.cpp * Update gray_code.cpp Remove extra lines, add bit_manipulation and gray_code namespaces, add negative number test
114 lines
4.0 KiB
C++
114 lines
4.0 KiB
C++
/**
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* @brief Program to generate n-bit [Gray
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* code](https://en.wikipedia.org/wiki/Gray_code)
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*
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* @details
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* Gray code is a binary numeral system
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* where consecutive values differ in exactly 1 bit.
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* The following code offers one of many possible Gray codes
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* given some pre-determined number of bits.
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*/
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#include <bitset> /// for gray code representation
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#include <cassert> /// for assert
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#include <iostream> /// for IO operations
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#include <vector> /// for vector data structure
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/**
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* @namespace bit_manipulation
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* @brief Bit manipulation algorithms
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*/
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namespace bit_manipulation {
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/**
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* @namespace gray_code
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* @brief Generate n-bit Gray code
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*/
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namespace gray_code {
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/**
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* @brief The main function to generate n-bit Gray code
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*
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* @param n Number of bits
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* @return A vector that stores the n-bit Gray code
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*/
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std::vector<std::bitset<32>> gray_code_generation(int n) {
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std::vector<std::bitset<32>> gray_code = {}; // Initialise empty vector
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// No Gray codes for non-positive values of n
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if (n <= 0) {
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return gray_code;
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}
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int total_codes = 1 << n; // Number of n-bit gray codes
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for (int i = 0; i < total_codes; i++) {
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int gray_num = i ^ (i >> 1); // Gray code formula
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gray_code.push_back(std::bitset<32>(gray_num)); // Store the value
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}
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return gray_code;
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}
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} // namespace gray_code
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} // namespace bit_manipulation
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/**
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* @brief Self-test implementation
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*
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* @returns void
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*/
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static void test() {
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std::vector<std::bitset<32>> gray_code_negative_1 = {};
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std::vector<std::bitset<32>> gray_code_0 = {};
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std::vector<std::bitset<32>> gray_code_1 = {
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std::bitset<32>(0), std::bitset<32>(1)
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};
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std::vector<std::bitset<32>> gray_code_2 = {
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std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2)
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};
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std::vector<std::bitset<32>> gray_code_3 = {
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std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2),
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std::bitset<32>(6), std::bitset<32>(7), std::bitset<32>(5), std::bitset<32>(4)
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};
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std::vector<std::bitset<32>> gray_code_4 = {
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std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2),
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std::bitset<32>(6), std::bitset<32>(7), std::bitset<32>(5), std::bitset<32>(4),
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std::bitset<32>(12), std::bitset<32>(13), std::bitset<32>(15), std::bitset<32>(14),
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std::bitset<32>(10), std::bitset<32>(11), std::bitset<32>(9), std::bitset<32>(8)
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};
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std::vector<std::bitset<32>> gray_code_5 = {
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std::bitset<32>(0), std::bitset<32>(1), std::bitset<32>(3), std::bitset<32>(2),
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std::bitset<32>(6), std::bitset<32>(7), std::bitset<32>(5), std::bitset<32>(4),
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std::bitset<32>(12), std::bitset<32>(13), std::bitset<32>(15), std::bitset<32>(14),
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std::bitset<32>(10), std::bitset<32>(11), std::bitset<32>(9), std::bitset<32>(8),
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std::bitset<32>(24), std::bitset<32>(25), std::bitset<32>(27), std::bitset<32>(26),
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std::bitset<32>(30), std::bitset<32>(31), std::bitset<32>(29), std::bitset<32>(28),
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std::bitset<32>(20), std::bitset<32>(21), std::bitset<32>(23), std::bitset<32>(22),
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std::bitset<32>(18), std::bitset<32>(19), std::bitset<32>(17), std::bitset<32>(16)
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};
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// invalid values for n
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assert(bit_manipulation::gray_code::gray_code_generation(-1) == gray_code_negative_1);
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assert(bit_manipulation::gray_code::gray_code_generation(0) == gray_code_0);
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// valid values for n
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assert(bit_manipulation::gray_code::gray_code_generation(1) == gray_code_1);
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assert(bit_manipulation::gray_code::gray_code_generation(2) == gray_code_2);
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assert(bit_manipulation::gray_code::gray_code_generation(3) == gray_code_3);
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assert(bit_manipulation::gray_code::gray_code_generation(4) == gray_code_4);
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assert(bit_manipulation::gray_code::gray_code_generation(5) == gray_code_5);
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}
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/**
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* @brief Main function
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* @returns 0 on exit
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*/
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int main() {
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test(); //Run self-test implementation
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return 0;
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}
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