Notebook

 Binary Search is a very trivial algorithm to search a target value from a sorted array. It's popular among students of computer science and also during interviews it gets asked by the interviewer. It's easy. We take an array of integers already sorted and apply binary search on that array to figure out if the target value does present in that sorted array or not.  The condition can be either present or not present. If it is present we return the array index of the element else we return -1. The algorithm is very simple, it's broken down into three parts. 1. Find and compare the middle element of the search space with the key. 2. If the key is found in the middle, just return the array index. 3. If the key is not found then choose half of the array space, based on whether the key value is smaller or greater than the mid element.       a. If the key element is smaller than the mid element, then the left side of the search space will be used otherwise, the right side of the s

T his is a very simple approach taken to generate the Fibonacci series through multithreading. Here instead of a function, used a function object. The code is very simple and self-explanatory.  #include <iostream> #include <mutex> #include <thread> class Fib { public:     Fib() : _num0(1), _num1(1) {}     unsigned long operator()(); private:     unsigned long _num0, _num1;     std::mutex mu; }; unsigned long Fib::operator()() {     mu.lock(); // critical section, exclusive access to the below code by locking the mutex     unsigned long  temp = _num0;     _num0 = _num1;     _num1 = temp + _num0;     mu.unlock();     return temp; } int main() {     Fib f;          int i = 0;     unsigned long res = 0, res2= 0, res3 = 0;     std::cout << "Fibonacci series: ";     while (i <= 15) {         std::thread t1([&] { res = f(); }); // Capturing result to respective variable via lambda         std::thread t2([&] { res2 = f(); });         std::thread t3(

 This is an attempt to run odd-even sorting from two threads without using locks. I have used a vector and split the vector logically in two halves if the size is beyond a value (Here as an example kept size 10, that means if the vector size is more than 10, then two threads will spawn and parallelize (on multi-core) sorting on the elements of the vector container. Finally, after sorting each half by two threads, another sorting will be arranged to make it finally sorted.  The Wiki contains the details about Odd-Even sorting. It's a comparison sorting. The below code snippet is a simple approach to odd-even sorting with multi-threading without having locks. No Extra space was allocated/used in this scenario.  void partBySort(std::vector<int>* vec, size_t begIndex, size_t endIndex) {     if (begIndex == endIndex) return;     bool isSorted = false;     while (!isSorted)     {         isSorted = true;         for (size_t i = begIndex; i <= endIndex - 1; i += 2)         {    

 The simplest sorting algorithm is not bubble sort or insertion sort but known as stupid sort aka gnome sort . The time complexity is like a bubble sort. However, the code base size is much smaller. Possibly it offers the smallest code base size in the domain of the sorting algorithm. The details can be found on Wikipedia . Here goes the code: void gnomeSort(std::vector<int>& data) {     int pos = 0;     while (pos < data.size())     {         if (pos == 0 or data[pos] >= data[pos - 1])             pos += 1;         else          {             std::swap(data[pos], data[pos - 1]);             pos -= 1;         }     } } int main() {        std::vector<int> v4 = { 10, 0, 2, 33, 5, 77, 8, 19, 1, 7 };       gnomeSort(v4);       for (auto i: v4)          std::cout << i << " "; } Happy sorting...

 I was trying to get Network Adapter Information from the Windows platform. So I have used an old API GetAdaptersInfo API . I was not sure whether it will work for Windows 10 but I have written a small sample to run on my Windows 10 PC and to my surprise, it still works. Though Microsoft recommended using  GetAdaptersAddresses API over GetAdaptersInfo API. It's a very small piece of code but the order headers are very important. If we do not follow the proper order the program won't compile. <Code> #include <iostream> #include <winsock2.h> #include <iphlpapi.h> #include <cassert> #pragma comment(lib, "iphlpapi.lib") void PrintMACAddress()  { DWORD _macAddress = 0; IP_ADAPTER_INFO _adapterInfo[16]; DWORD dwBufLen = sizeof(_adapterInfo); DWORD dwStatus = GetAdaptersInfo(_adapterInfo, &dwBufLen); assert(dwStatus == ERROR_SUCCESS); PIP_ADAPTER_INFO _pAdapterInfo = _adapterInfo; char string[32]; do { sprintf_s(string,

  We are aware of the Binomial coefficient, which is a mathematical term used to  represent the number of ways to select a certain number of items/objects from a larger set, without regard to their order. It's denoted by a symbol C(n, k)(n choose k or n over k). It gets computed by following formula:  C(n, k) = n! / (k! * (n - k)!)   The C++ implementation using the above formula is:  int factorial( int n) {     if (n <= 1 )         return 1 ;     else         return n * factorial(n - 1 ); } int binomialCoefficient( int n, int r) {     if (r > n)         return 0 ;     int numerator = factorial(n);     int denominator = factorial(r) * factorial(n - r);     int result = numerator / denominator;     return result; } int main() {      std::cout << "Value of C(" << 5 << ", " << 2 << ") is "          << binomialCoefficient( 5 , 2 ) << "\n" ; } So, the number of ways to choose two i

  Sometimes we've seen some application or process that can't be debugged using any debugger. As soon as we attach a debugger, either the application will terminate or pop up a message like a debugger attached with the process, so terminating the application. What so ever, in windows world, there is an API, which detects if the process is being debugged or not.  It's IsDebuggerPresent() Win32 API. You can refer to the  MSDN  link to get more details on it. So, I've written a test sample below: #include <Windows.h> int _tmain(int argc, _TCHAR* argv[]) {     if (IsDebuggerPresent() == TRUE)     {           MessageBox(NULL,            TEXT("Please close your debugging                 application and restart the program"),            TEXT("Debugger Found!"), 0);         ExitProcess(0);     }     MessageBox(NULL, TEXT("Hello World!"), TEXT("Bypassed"), 0);     ExitProcess(0);     return 0; } As usual, I did compile the code usin