Solidity Basics

Create a contract that can store data and return the data back, be able to do the following

1. recieve information
2. store information
3. return the information back

Steps:

• It's statically typed

• Comments starts with two forward slashes // Some Comments in solidity

• [Pragma]

  • First line of solidity file is the pragma statement. It indicates the solidity version that is being used, helps to ensure compatibility in files pragma solidity ^0.8.2;

• [SmartContract]

  • A contract in the sense of solidity is a collection of code (its functions) and data (its state) that resides ar a specific address on the etherem blockchain.
  • Happens when we deploy smart contract

  contract [name_of_contract] {
    uint storeData;
    string names;
    bool switchON;
  }
  

  • Creates object for us with some name name_of_contract. write functions and state inside the contract.
  • Create a variable of storeData and it's data type uint as integer

• [Variables]: Variables are reserved memory location to store value.

  • Data types can be of character, integer, boolean, floating point, double floating point, boolean
  • unit storeData = '5' it returns a integer data type. Here it is 5
  • string names = 'john' it returns a string data type. Here it is john
  • bool switchON = false it returns a boolean data type. Here it is false

• [Functions]

  • A function is a group of reusable code that can be used anywhere in the application.
  • They perform a specific operation/task
  • The most common way to define a function in solidity is by using the functions keyword, followed by unique function name, a list of parameters.
  • set function public, it enables visibility so that we can call this outside of the contract, private, it we didn't want to accessbility outside the function
  • retrieve function return value of storeData, to make it visibility use public keyword and view:
    • it is a global modifiers which tells us function that it can't modify the state. helps us to clear off warnings, otherwise we are going to be returning something for the data.
    • Also we want to ensure that it's not going to be modified the state of the contract
    • returns: It is different than return storeData. It is related with function itself returns (uint): return for the contracts an integer

  function storeFun(unit x) public{
    storeData = x;
  }
  
  function getStoreFun() public view returns (uint) {
    return storeData;
  }
  

  [view]: does not modify the state [returns]: it does return for the contracts an integer