Adding 2nd assignment - recursion

Fundamental_Recursion/main.cpp

@@ -0,0 +1,89 @@
+#include <chrono>
+#include <iostream>
+#include "Utils.h"
+
+static void line(const char* title)
+{
+    std::cout << "\n======= " << title << "=======\n";
+}
+
+int main()
+{
+    line("Neutral numbers");
+    printNaturalNumber(10);
+    std::cout << "\n";
+
+
+    line("Factorial");
+    const int fact_expect[] = {
+        1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800
+    };
+    bool ok_fact = true;
+    for (int n = 0; n <= 10; ++n) {
+        int r = calculateFactorial(n);
+        std::cout << "n=" << n << " -> " << r
+                  << (r == fact_expect[n] ? "  OK" : "  MISMATCH") << "\n";
+        ok_fact &= (r == fact_expect[n]);
+    }
+
+
+    line ("Power");
+    struct Case { int base, exp, expect; };
+    const Case pow_cases[] = {
+        {2,0,1}, {2,1,2}, {2,5,32}, {3,4,81}, {5,3,125}, {10,2,100}
+    };
+    bool ok_pow = true;
+    for (auto c : pow_cases) {
+        int r = power(c.base, c.exp);
+        std::cout << c.base << "^" << c.exp << " = " << r
+                  << (r == c.expect ? "  OK" : "  MISMATCH") << "\n";
+        ok_pow &= (r == c.expect);
+
+        line("Fibonacci");
+        const int fib_expect[] = {0,1,1,2,3,5,8,13,21,34,55,89,144};
+        bool ok_fib = true;
+        for (int n = 0; n <= 12; ++n) {
+            int r = fibonacci(n);
+            std::cout << "F(" << n << ") = " << r
+                      << (r == fib_expect[n] ? "  OK" : "  MISMATCH") << "\n";
+            ok_fib &= (r == fib_expect[n]);
+        }
+
+
+        line("Count occurrences");
+        std::string s = makeRandomString(2000, 'a', 'f');
+        char target = 'c';
+        int rec = countOccurrences(s, target);                                          //<--- recursive
+        int ref = static_cast<int>(std::count(s.begin(), s.end(), target));
+        std::cout << "recursive=" << rec << "  std::count=" << ref
+                  << (rec == ref ? "  OK" : "  MISMATCH") << "\n";
+        double t_rec_ms = time_ms([&]{ (void)countOccurrences(s, target); });
+        std::cout << "perf (recursive substr): ~" << t_rec_ms << " ms\n";
+
+
+        line ("Find largest element");
+        constexpr int N = 100000;
+        int* arr = new int[N];
+        fillRandomArray(arr, N, -100000, 100000);
+        double t_my_ms  = time_ms([&]{ (void)findLargestElement(arr, N); });
+        int myMax = findLargestElement(arr, N);
+        int stdMax = *std::max_element(arr, arr + N);
+        std::cout << "myMax=" << myMax << "  stdMax=" << stdMax
+                  << (myMax == stdMax ? "  OK" : "  MISMATCH") << "\n";
+        std::cout << "perf (recursive): ~" << t_my_ms << " ms\n";
+        delete[] arr;
+
+
+        line("Traverse Ascii table");
+        traverseAsciiTable('A', 'F');
+        std::cout << "\n";
+
+
+        line("Summary");
+        std::cout << "Factorial: " << (ok_fact ? "OK" : "FAIL") << "\n";
+        std::cout << "Power:     " << (ok_pow  ? "OK" : "FAIL") << "\n";
+        std::cout << "Fibonacci: " << (ok_fib  ? "OK" : "FAIL") << "\n";
+
+        return 0;
+    }
+}