Data types (uint, int, bool, address, string) in Blockchain / Solidity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a uint in blockchain programming?

A uint is an unsigned integer data type that stores only non-negative whole numbers (0 and above). It cannot hold negative values.

beginner

How does an int differ from a uint?

An int is a signed integer that can hold both negative and positive whole numbers, while a uint holds only non-negative numbers.

beginner

What values can a bool data type hold?

A bool can hold only two values: true or false. It is used to represent yes/no or on/off states.

beginner

What is the purpose of the address data type in blockchain?

The <strong>address</strong> type stores a blockchain account's unique identifier. It is used to hold wallet or contract addresses.

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What kind of data does the string type store?

The string type stores text data, like words or sentences, made up of characters.

Which data type can store negative numbers?

A int

B address

C bool

D uint

Only int can store negative numbers. uint stores only zero or positive numbers.

What values can a bool hold?

A Any number

B True or False

C Text strings

D Blockchain addresses

bool holds only true or false.

Which data type is used to store a wallet or contract identifier?

A address

B bool

C string

D int

address stores blockchain account addresses.

What type of data does string hold?

A Blockchain addresses

B True or False

C Numbers only

D Text characters

string holds text made of characters.

Which data type cannot hold negative values?

A int

B bool

C uint

D string

uint is unsigned and cannot hold negative numbers.

Explain the difference between int and uint data types.

Think about whether the number can be below zero.

Describe the purpose of the address data type in blockchain.

It holds where money or contracts live on the blockchain.