::_1, placeholders::_2, 4.0);
function Plus2 = bind(Plus, placeholders::_1, placeholders...::_2, 4.2);
function Plus3 = bind(Plus, placeholders::_1, placeholders::_2, 4.4);...::_1, placeholders::_2无视bind函数包装器的常量位置:按顺序1,2,3…
如下图所示:
即使rate参数放在bind包装器的中间,依然按照placeholders::_1,_2,...::_1, 4.0 placeholders::_2);
function Plus2 = bind(Plus, placeholders::_1, 4.2,placeholders...::_2);
function Plus3 = bind(Plus, placeholders::_1,4.4 ,placeholders::_2);
cout