第20666题 单选
C++实现区块链addBlock添加区块函数,横线处应填入的正确代码是?

区块链技术是比特币的基础。在区块链中,每个区块指向前一个区块,构成链式列表,新区块只能接在链尾,不允许在中间插入或删除。相关代码结构如下: 区块链实现代码结构

A
Block* newBlock = new Block(tail->index + 1, data, tail);
tail = newBlock->prev;
B
Block* newBlock = new Block(tail->index + 1, data, tail);
tail = newBlock;
C
Block* newBlock = new Block(tail->index + 1, data, tail->prev);
tail = newBlock;
D
Block* newBlock = new Block(tail->index + 1, data, tail->prev);
tail = newBlock->prev;