Add examples for different utilities

Change-Id: I7ba2435c9ffaa10ccb67a87693ac961a26341ffe

cpplinker/09_debug_linker/main.cpp

@@ -0,0 +1,27 @@
+#include "math_lib.hpp"
+#include <iostream>
+
+int main() {
+    // --- Free functions ---
+    std::cout << "=== Free functions ===\n";
+    std::cout << "Math::sqrt(2.0)    = " << Math::sqrt(2.0)   << "\n";
+    std::cout << "Math::square(5.0)  = " << Math::square(5.0) << "\n";
+    std::cout << "Math::cube(3.0)    = " << Math::cube(3.0)   << "\n";
+
+    // --- Vector2D ---
+    std::cout << "\n=== Vector2D ===\n";
+    Math::Vector2D v1(3.0, 4.0);
+    Math::Vector2D v2(1.0, 2.0);
+
+    std::cout << "v1.length()         = " << v1.length() << "\n";
+
+    Math::Vector2D sum = v1.add(v2);
+    std::cout << "v1.add(v2)          = (" << sum.x << ", " << sum.y << ")\n";
+
+    Math::Vector2D scaled = v1.scale(2.0);
+    std::cout << "v1.scale(2.0)       = (" << scaled.x << ", " << scaled.y << ")\n";
+
+    std::cout << "v1.dot(v2)          = " << v1.dot(v2) << "\n";
+
+    return 0;
+}