Skip to main content


Showing posts with the label multi-threading

A simple approach to generate Fibonacci series via multi-threading

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(

An Attempt to run Odd-Even Sorting in multi-threading

 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)         {