How to set position use anchor point Vec2(0.5, 0.5) like cocos creator?

How to set position in center of parent node with anchor point (0.5, 0.5) like cocos creator do in c++?

auto parentNode = Node::create();
parentNode->setContentSize(Size(200, 200));

// child
auto sprite = Sprite::create("sample.png");
sprite->setAnchorPoint(Vec2::ANCHOR_MIDDLE);  // (0.5, 0.5)
sprite->setPosition(parentNode->getContentSize() / 2);

parentNode->addChild(sprite);

How to set this without set position, only change anchor point only?

No. In C++, both coordinates and anchor points must be explicitly set.