implemented selection sort

selection_sort/Main.cpp

@@ -1,6 +1,120 @@
+#include <chrono>
 #include <iostream>
 
+#define MAX_SIZE 1000000
+
+long getNanos() {
+    return std::chrono::high_resolution_clock::now().time_since_epoch().count();
+}
+
+long getMillis() {
+    return std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now().time_since_epoch()).count();
+}
+
+int intKey(const int& i) {
+    return i;
+}
+
+static unsigned long seed = 0;
+
+int randomInt() {
+    seed = (seed * 0x5DEECE66DL + 0xBL) & 0xFFFFFFFFFFFF;
+    return static_cast<int>(seed >> 17);
+}
+
+template<typename T>
+void selectionSort(T* in, int size, int (*key)(const T&)) {
+    unsigned int minValue;
+    // move boundry of unsorted array one by one
+    for (unsigned int i = 0; i < size - 1; i++) {
+        // find the minimum element in the unsorted array
+        minValue = i;
+        for (unsigned int j = i + 1; j < size; j++) {
+            if (key(in[j]) < key(in[minValue])) {
+                minValue = j;
+            }
+        }
+
+        // swap the minimum element with the current element
+        T val = in[minValue];
+        in[minValue] = in[i];
+        in[i] = val;
+    }
+}
+
+void cacheTest() {
+    for (int size = 512; size < MAX_SIZE; size *= 2) {
+        printf("Cache Test with size = %9d | ", size);
+        constexpr int max = 500;
+        int* a = new int[size];
+        seed = 0;
+        for (int i = 0; i < size; i++) {
+            a[i] = randomInt() % max;
+        }
+        long time = -getMillis();
+        selectionSort(a, size, intKey);
+        time += getMillis();
+        printf("%10ld ms | %7.2lf ms / entry \n", time,
+            (static_cast<double>(time) / size));
+        delete[] a;
+    }
+}
+
+struct A {
+    int key;
+    char filler[32];
+};
+
+int aKey(const A& a) {
+    return a.key;
+}
+
+void structTest() {
+    for (int size = 512; size < MAX_SIZE; size *= 2) {
+        printf("Struct Test with size = %9d | ", size);
+        constexpr int max = 500;
+        A* a = new A[size];
+        seed = 0;
+        for (int i = 0; i < size; i++) {
+            a[i].key = randomInt() % max;
+        }
+        long time = -getMillis();
+        selectionSort(a, size, aKey);
+        time += getMillis();
+        printf("%10ld ms | %7.2lf ms / entry \n", time,
+            (static_cast<double>(time) / size));
+        delete[] a;
+    }
+}
+
+int pointerKey(int* const& a) {
+    return *a;
+}
+
+void pointerTest() {
+    for (int size = 512; size < MAX_SIZE; size *= 2) {
+        printf("Pointer Test with size = %9d | ", size);
+        constexpr int max = 500;
+        int** a = new int* [size];
+        seed = 0;
+        for (int i = 0; i < size; i++) {
+            a[i] = new int(randomInt() % max);
+        }
+        long time = -getMillis();
+        selectionSort<int*>(a, size, pointerKey);
+        time += getMillis();
+        printf("%10ld ms | %7.2lf ms / entry \n", time,
+            (static_cast<double>(time) / size));
+        for (int i = 0; i < size; i++) {
+            delete a[i];
+        }
+        delete[] a;
+    }
+}
+
 int main() {
-    std::cout << "Test\n";
+    cacheTest();
+    structTest();
+    pointerTest();
     return 0;
-}
+}