C++11 function函數用法

// C++11 function 
#include <functional>
void print_num(int i)
{
	std::cout << i << '\n';
}
void testFunctionTpl()
{
	// templet 匿名函數
	std::function<void(const int&, const int&)>getSum = [&](const int &nI1, const int &nI2)
	{
		int nSum = nI1 + nI2;
		std::cout << nSum << endl;
	};
	 getSum(8, 9);

	 //  lambda
	 std::function<void()> f_display_42 = []() { print_num(42); };
	 f_display_42();


	 //********************* 測試成員函數 begin*********************//
	 class TestClass
	 {
	 public:
		 TestClass(int i) : m_nI(i){}
		 ~TestClass() {}
		 void testMemberFunc(int i) const { std::cout << m_nI + i << endl; }
		 int  testResultFun(int i) const { return m_nI + i; }
		 void testBindFun(int num) const { std::cout << m_nI + num << endl; }
		 int m_nI;
	 };

	 
	 std::function<void(const TestClass&, int)> testMemberFunc = &TestClass::testMemberFunc;
	 const TestClass oTestObject(100);
	 // 傳對象
	 testMemberFunc(oTestObject, 100);
	 // 會根據模板構造對象
	 testMemberFunc(300, 100);
	 //  返回值成員函數
	 std::function<int(const TestClass&, int)> testResultFun = &TestClass::testResultFun;
	 int nRet = testResultFun(oTestObject, 100);
	 std::cout << nRet << endl;
	 // 成員變量
	 std::function<int(const TestClass&)> f_num = &TestClass::m_nI;
	 std::cout << "m_nI: " << f_num(oTestObject) << '\n';

	 // 對象形式調用成員函數
	 using std::placeholders::_1; // 占位符 
	 std::function<void(int)> testBindFun = std::bind(&TestClass::testBindFun, oTestObject, _1);
	 testBindFun(222);

	 // 指針形式調用成員函數
	 std::function<void(int)> testBindFun2 = std::bind(&TestClass::testBindFun, &oTestObject, _1);
	 testBindFun2(333);
	 //********************* 測試成員函數 end*********************//

	 //********************* 測試普通函數 begin*********************//

	 // 綁定普通函數
	 std::function<void()> f_display_31337 = std::bind(print_num, 31337);
	 f_display_31337();
	 //********************* 測試普通函數 end*********************//

	 // bad_function_call
	 std::function<int()> f = nullptr;
	 try {
		 f();
	 }
	 catch (const std::bad_function_call& e) {
		 std::cout << e.what() << '\n';
	 }
	 
}
int main() 
{
	testFunctionTpl();
	int i = 0;
}