C with classes

ObjectOrientedProgramming/OOP/oop_hw2/oop_hw2_5/Q5.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+
+class Demo {
+private:
+    int mNum;
+    static Demo* instance;
+    Demo() : mNum(0) {}
+public:
+    static Demo* GetInstance() {
+        if (!instance) instance = new Demo();
+        return instance;
+    }
+    void AddValue(int value) { mNum += value; }
+    void ShowValue() const { std::cout << "Value=" << mNum << std::endl; }
+};
+Demo* Demo::instance = NULL;
+
+void Test() {
+    Demo::GetInstance()->AddValue(10);
+    Demo::GetInstance()->AddValue(5);
+    Demo::GetInstance()->ShowValue();
+}
+
+int main(){
+	Test(); 
+	return 0;
+}