Blockchain Developer Certification Practice

What type of function in Solidity can only be called by the smart contract instance itself?

1. Public

2. Private

3. View

4. Payable

The correct answer is: Private

In Solidity, a private function is designed specifically to be called only from within the same contract. This encapsulation ensures that the function cannot be accessed or executed by external contracts or users. Private functions are useful for implementing internal logic and maintaining control over sensitive operations within the contract without exposing them to external interactions. Public functions, on the other hand, can be accessed both internally and externally, meaning they can be called by other contracts and accounts, which distinguishes them from private functions. View and payable functions pertain to specific behaviors related to state reading and Ether transactions, but do not restrict access to the calling contract in the same way that a private function does. Therefore, understanding the access control features of private functions in Solidity is essential for managing the internal functionality of smart contracts securely and effectively.