Debounce function - Facebook

Author: offamitkumar

Solution/Day-105.cpp

@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+#include <stdexcept>
+using namespace std;
+using namespace chrono;
+
+function<void()> Debounced(function<void()>&f , int period){
+    static auto created = high_resolution_clock::now();
+    function<void()> fn = [=,&f](){
+        auto now = high_resolution_clock::now();
+        if (duration_cast<milliseconds>(now - created).count() > period){
+            f();
+        }
+        // created = now; // mark the last call of the function 
+
+        // For debouncing uncomment the above line, So we will mark the time for last 
+        // call made to this function and would call it again only if time difference is greater
+        // then the period provided
+    };
+    return fn;
+}
+
+int main(void){
+    int x = 0;
+    function<void()> f = [&x](){
+        x++;
+    };
+
+    auto dbf = Debounced(f, 500);
+    for (int i = 0; i < 10; ++i) {
+      dbf();
+    }
+    // we can't call this function until 500ms period is over.
+    if (x != 0) {
+      throw std::runtime_error("Expected x not to change since it's debounced for 500ms");
+    }
+    std::this_thread::sleep_for(milliseconds(501)); // 500 (inclusive) is threshold so let the 
+    // thread sleep for 501ms
+
+    // now we can call this function as many time we want
+    for (int i = 0; i < 10; ++i) {
+      dbf();
+    }
+    if (x != 10) {
+      throw std::runtime_error("Expected x to be incremented 10 times");
+    }
+}