C++中的Lambda函数详解

[capture](parameters) -> return_type { /* ... */ }

[]        //表示的是在lambda定义之前的域，对外部参数的调用；
[=]       //表示外部参数直接传值
[&]       //表示外部参数传引用，可修改值。当默认捕获符是 & 时，后继的简单捕获符必须不以 & 开始。而当默认捕获符是 = 时，后继的简单捕获符必须以 & 开始。
[x, &y]   //x is captured by value, y is captured by reference
[&, x]    //x is explicitly captured by value. Other variables will be captured by reference
[=, &z]   //z is explicitly captured by reference. Other variables will be captured by value

    std::function<int(int,int)> add = [](int a,int b) ->int {  return a + b;   };

    auto add = [](int a,int b) ->int {  return a + b;   };

    auto add = [](int a,int b) ->int {  return a + b;   };
    int result  = add(1,2);

auto add = [](int a,int b) ->int {  return a + b;   };
int(*func_ptr)(int,int) = add ;
int result = func_ptr(1,2);

    connect(sys, &SYSClass::sig_1, this, [=](int index)
    {
        ......
    });

    QTimer::singleShot(mTime,widgetPtr,[=]()
    {
        QPropertyAnimation *pAnimation = new QPropertyAnimation(widgetPtr,"windowOpacity",widgetPtr);
        pAnimation->setDuration(1000);
        pAnimation->setEasingCurve(QEasingCurve::InCirc);
        pAnimation->setStartValue(1.0);
        pAnimation->setEndValue(0.0);
        pAnimation->start();
        connect(pAnimation,&QPropertyAnimation::finished,[=]{
            delete widgetPtr;
        });
    });

std::sort( floatList, floatList + N, [](float a, float b) 
		{
            return a < b;
        });