Traditional Thread

C++ 11 supports multi-threading, for which we previously used pthread or boost. Standard C++ 11’s threading is based on boost::thread, now it’s cross platform and no dependency needed.

#include <thread>
#include <iostream>
int testThread()
{
	std::cout << "I am a seperate thread...";
}
void main()
{
	std::thread newThread(testThread);//now it's running
        //do something else .... //
	newThread.join();//before the ending, newThread should join
        return;
}

The code is simple, the thread function will run right after the std::thread is declared.

Function binding

std::bind can create a function which is binded to another one:

void originalFunc(int a, double b, string c)
{
	cout << a << " " << b << " " << c.c_str() << endl;
}//original function, to be binded

void main()
{
  	//Newly binded function, created by bind function
  	auto newlyBindedFunc = bind(originalFunc, 
                                placeholders::_2, 
                                10.5,
                                placeholders::_1);
	newlyBindedFunc("Hello world",2);//call the new func
        originalFunc(2,10.5,"Hello world");//the same result
}

lambda expression can be understood as an anonymous function, it doesn’t need a name, it is created in runtime:

auto lam1 = []()
{
  cout<<"Hello World!";
};
lam1();

The code above shows a simplest lambda expression, when lam1() is called, it will print “Hello World!”.

How is the lambda expression existed in C++?

It is existed a closure class, each lambda is a unique closer class generated by the compiler in runtime. So it is a object and can be copied:

shared_ptr is a pointer allowed to be copied, it is like the normal pointer we use, but it’s smart for its counting function.

A normal pointer is not safe as when we are deleting it, we don’t know if someone else is using it. The shared_ptr count the users of this pointer, when someone release the pointer, its count will decrement, the memory block where it points will release only when the count becomes 0, which means no one is using it.

Initialize a shared_ptr:

shared_ptr<int> s{ new int{3} };

It can also be “made”, even made directly from value:

You should include when using smart pointers

unique_ptr

Just as its name means, unique_ptr guarantees that there is only one pointer point to a specific memory block. So it cannot be copied by only moved.

Init a unique_ptr

unique_ptr<int> p{ new int };
unique_ptr<int> p{ new int{4} };

As you can see, smart pointers are wraps of normal pointers, we call them “raw” pointers.

constexpr is more strict than const

int a;
const b = a;//correct
constexpr c = a;//wrong, because a has no value yet

When declaring a constexpr, it should be assigned with a already existed value.

you can get compile-time result when using constexpr function

Alias is preferred to typedef

It is clearer:

typedef void (*FP)(int, const std::string&); // old way: typedef
using FP = void (*)(int, const std::string&); // new way: alias

It support template:

template<typename T>
using MyAllocList = std::list<T, MyAlloc<T>>;

enum is preferred to be scoped

Comparison between the old and new way:

DataBinding and MVVM Pattern

When dealing with GUI, usually we will use the MVC pattern, which means we manage a set of data as Model, the model will be demonstrated as View and the Contoller controls the logic of showing the data:

mvc_role_diagram

The main problem of this pattern is that most of the controller’s works are simple “get” and “set” functions between the data and the gui Like: