The Complete Solidity Course - Zero to Advanced for Blockchain and Smart Contracts - Global Variables in Solidity I

The video tutorial introduces global variables in Solidity, focusing on their role and examples like msg.sender and msg.value. It explains how these variables provide blockchain information and are accessible throughout a contract. The tutorial includes a practical example of creating a Ledger Balance contract using these variables. It concludes with an exercise to create a new contract that inherits from the Ledger Balance contract, reinforcing the concepts learned.

What is the primary purpose of global variables in Solidity?

• To store local data within a function

• To define the structure of a contract

• To provide information about the blockchain

• To manage user input

Which global variable in Solidity represents the sender of a message?

• tx.origin

• msg.sender

• msg.value

• block.timestamp

In the 'Ledger Balance' contract, what is used to update the balance of the current caller?

• block.number

• msg.sender

• msg.value

• tx.gasprice

What is the key data type used in the mapping for the 'Ledger Balance' contract?

• address

• string

• bool

• uint

What is the first step in creating a new contract that inherits from 'Ledger Balance'?

• Deploy the existing contract

• Create a new contract called 'Updater'

• Update the balance

• Define a new function

What should you do after creating a new variable for the 'Ledger Balance' contract in the exercise?

• Compile the contract

• Update the balance to 100

• Set the variable to a new instance of 'Ledger Balance'

• Deploy the contract

What is the final step in the exercise involving the 'Updater' contract?

• Use 'msg.value' to set the balance

• Compile the contract

• Update the ledger balance by 30

• Deploy only the 'Updater' contract