add intro c++

CPlusPlus/intro/main.cpp

@@ -0,0 +1,126 @@
+#include <iostream>
+#include <Windows.h>
+#include <memory>
+#include "functions.h"
+#include "ClassA.h"
+
+int number = 0;
+
+using namespace std;
+
+void functionB() {}
+void functionC();
+void functionD(); // forward declaration
+
+int main()
+{
+	//std::cout << "Hello World!" << std::endl;
+	//cout << "Hallo" << endl;
+
+	////functionA(); // compiler error - function not defined
+	//functionB(); // no error
+	////functionC(); // linker error - function declared, but not defined
+	//functionD(); // no error
+	////functionE(); // linker error - function is defined twice, because of two includes in two source files
+	//functionF(); // no error
+
+	//short s = 0;
+	//unsigned short us = 0;
+	//int i = 0;
+	//long l = 0;
+
+	//cout << "size of short: " << sizeof(s) << endl;
+	//cout << "size of int: " << sizeof(i) << endl;
+	//cout << "size of long: " << sizeof(l) << endl;
+	//cout << "size of long long: " << sizeof(long long) << endl;
+	//cout << "size of bool: " << sizeof(bool) << endl;
+
+	//BYTE b;
+
+	//cin >> number;
+	//cout << "number: " << number << endl;
+
+	//char c;
+	//cin >> c;
+	//cout << "c: " << c << endl;
+
+	//string str;
+	//cin >> str;
+	//cout << "str: " << str << endl;
+
+	//char sz[128];
+	//cin >> sz;
+	//cout << "sz: " << sz << endl;
+	//cin >> sz;
+	//cout << "sz: " << sz << endl;
+
+	//int numbers[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+	//int* pNumber = new int(0);
+
+	//cout << "local array print" << endl;
+	//for (size_t i = 0; i < sizeof(numbers) / sizeof(int); i++)
+	//{
+	//	std::cout << numbers[i] << " ";
+	//}
+	//std::cout << std::endl;
+
+	//cout << "function array print" << endl;
+	//printArray(numbers, size(numbers));
+
+	//int n = 1;
+	//changeInt(n);
+	//cout << "n (" << &n << "): " << n << endl;
+	//changeIntPointer(&n);
+	//cout << "n (" << &n << "): " << n << endl;
+
+	//int* pN = nullptr;
+	//int* pN2 = new int;
+	//*pN2 = 1234;
+	//delete pN2;
+	//pN2 = nullptr;
+
+	//if (pN2 != nullptr)
+	//{
+	//	*pN2 = 1234;
+	//}
+
+	//pN = new int;
+	//*pN += 10;
+	//pN = new int; // BAD - Memory Leak
+
+	//changeIntReference(n);
+	//cout << "n (" << &n << "): " << n << endl;
+
+	//unique_ptr<int> un = make_unique<int>(0);
+	//*un = 10;
+	////unique_ptr<int> un2 = un; // not possible, because it is unique
+
+	//shared_ptr<int> sn = make_shared<int>(0);
+	//*sn = 10;
+	//cout << "sn refs: " << sn.use_count() << endl;
+	//shared_ptr<int> sn2 = sn;
+	//cout << "sn refs: " << sn.use_count() << endl;
+	//sn.reset();
+	//cout << "sn refs: " << sn.use_count() << endl;
+	//cout << "sn2 refs: " << sn2.use_count() << endl;
+
+	//weak_ptr<int> wn = sn2;
+	//cout << "sn2 refs: " << sn2.use_count() << endl;
+	//if (!wn.expired()) 
+	//{
+	//	shared_ptr<int> ln = wn.lock();
+	//	*ln *= 23;
+	//	cout << "sn2 refs: " << sn2.use_count() << endl;
+	//}
+
+	//cout << "sn2 refs: " << sn2.use_count() << endl;
+
+	ClassA classA;
+	ClassA classA2 = classA;
+
+	return 0;
+}
+
+void functionA() {}
+
+void functionD() {}