Mastering Blockchain Programming with Solidity

The _burn internal function

_burn() is an internal function, which is used to burn a given NFT from the owner's account.

This function takes two arguments:

• owner: The address of the owner whose token is to be burned
• tokenId: The NFT Id that is to be burned from the owner's account

Let's look at the _burn() function code:

function _burn(address owner, uint256 tokenId) internal {    require(ownerOf(tokenId) == owner);    _clearApproval(tokenId);    _ownedTokensCount[owner] = _ownedTokensCount[owner].sub(1);    _tokenOwner[tokenId] = address(0);    emit Transfer(owner, address(0), tokenId);}

The code first checks that the provided owner address is correct and is actually the owner of the given tokenId. Then, it clears all of the approval entries from the ...