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Vedant Chainani
Vedant Chainani

Posted on • Originally published at dev.to

Day 6 - Data Types

GitHub logo Envoy-VC / 100-Days-of-Solidity

100 Days of Solidity step-by-step guide to learn Smart Contract Development.

This is Day 6 of 100 in Solidity Series
Today I Learned About Data Types in Solidity.

Data Types

Solidity offers the programmer a rich assortment of built-in as well as user defined data types. Following table lists down seven basic C++ data types βˆ’

Type Keyword Values
Boolean bool true/false
Integer int/uint Signed and unsigned integers of varying sizes.
Integer int8 to int256 Signed int from 8 bits to 256 bits. int256 is the same as int.
Integer uint8 to uint256 Unsigned int from 8 bits to 256 bits. uint256 is the same as uint.
Fixed Point Numbers fixed/ufixed Signed and unsigned fixed point numbers of varying sizes.
Fixed Point Numbers fixedMxN Signed fixed point number where M represents number of bits taken by type and N represents the decimal points. M should be divisible by 8 and goes from 8 to 256. N can be from 0 to 80. fixed is same as fixed128x18.
Hexadecimal address Holds a 20 byte value (size of an Ethereum address).

example -

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.7;

contract MyTypes {
    bool myBool = true; // if bool value is not specified then it is false by default

    // Unsigned Integers - can only take 0 or positive values range =  0 - (2^n - 1)
    uint8 myUint8 = 84; // 0 - 255
    uint16 myUint16 = 1458; // 0 - (2^16 -1)
    uint256 myUint256 = 47452848525; // uint goes from 8 to 256 taking steps of 8 and can hold max number which is equal to ( 2^n -1 )

    // Signed Integers - can take negative as well as positive values Range = (-2^(n-1),2^n - 1)
    int8 myInt8 = -114; // -128 - 255
    int16 myInt16 = -1458; // -32768 - 65535
    int256 myInt256 = 47452848525; // int goes from 8 to 256 taking steps of 8

    // address - Holds a 20 byte value (size of an Ethereum address).
    // address refers to a smart contract address
    // address payable refers to a wallet address which can recieve or send funds
    address myAddress; //Defaults to 0x0000000000000000000000000000000000000000
    address public smartAddress = address(0x7EF2e0048f5bAeDe046f6BF797943daF4ED8CB47);
    address payable walletAddress = payable(0xBF4979305B43B0eB5Bb6a5C67ffB89408803d3e1);
}
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