The Complete Solidity Course - Zero to Advanced for Blockchain and Smart Contracts - What Are Function Modifiers in Soli

The video tutorial introduces function modifiers in Solidity, explaining their role in modifying function behavior. It covers contract inheritance, common errors, and the structure of contract code, including mappings and variables. The tutorial also discusses visibility keywords and how function modifiers can be customized to define specific behaviors, contrasting them with preset keywords like 'public'.

What is the primary purpose of function modifiers in Solidity?

• To change the visibility of a function

• To delete a function

• To modify the behavior of a function

• To define a new function

In the example contract 'register', what does the keyword 'is' signify?

• It signifies inheritance from another contract

• It indicates a function call

• It denotes a variable declaration

• It is used to define a new contract

What is the role of the 'mapping' in the 'register' contract?

• To map addresses to boolean values

• To store a list of integers

• To define a new function

• To change the contract's owner

What does the 'register' function do in the contract?

• It changes the contract's owner

• It sets the message sender's address to true

• It modifies the contract's price

• It deletes an address from the mapping

How does the 'change price' function operate in the contract?

• It sets a new price based on input

• It deletes the current price

• It doubles the current price

• It resets the price to zero

How do function modifiers differ from keywords like 'public'?

• Modifiers are preset and cannot be changed

• Modifiers are used to delete functions

• Modifiers are customizable and defined by the user

• Modifiers are used only for visibility

What is a key characteristic of function modifiers?

• They are used to create new contracts

• They are only used for inheritance

• They are customizable by the developer

• They are always public