Solidity Variables Quiz

Which of the following is a global variable in Solidity?

• msg.sender

• owner

• localCounter

• stateCounter

Which of the following global variables is automatically provided by Solidity?

• msg.data

• block.coinbase

• tx.origin

• All of the above

Which type of variable is stored persistently on the blockchain?

• Global variable

• State variable

• Local variable

• Temporary variable

What is the scope of a local variable declared inside a function?

• Function level

• Contract level

• Global scope

• Block level

Which of the following is true about the memory keyword in Solidity?

• It is used for persistent storage on the blockchain.

• Variables declared in memory exist only during function execution.

• It makes a variable read-only.

• It stores variables permanently within the contract.

Which statement is true regarding global variables like msg.sender and block.timestamp?

• They can be modified within functions.

• They are read-only and cannot be altered.

• They can only be modified in payable functions.

• They can be reassigned to local variables to change their values.

What is the primary difference between local and state variables in Solidity?

• Local variables are stored on the blockchain, state variables are not.

• State variables are stored in memory, while local variables are stored in storage.

• State variables persist on the blockchain, whereas local variables exist temporarily during execution.

• There is no difference; they are treated the same by the compiler.

Where should state variables be declared in a Solidity contract?

• Inside a function

• At the contract level (outside any function)

• Within a library

• Inside a struct

Which of the following reference types cannot be declared with the memory keyword in Solidity?

• Arrays

• Mappings

• Structs

• Strings

When assigning a state variable of a value type (e.g., uint) to another variable, what happens?

• A new copy of the value is created

• A reference to the original variable is created

• It depends on whether the variable is marked as constant

• It results in a compilation error