ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract A{
    uint private x= 100;
    uint public y =200;
    address private addr = msg.sender;

    function fun1() public pure returns(string memory){

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract Events{

    //event is used to set the values on blockchain.
    event balance(address account,string message,uint val);

    //this function transaction function or simple function because its have no return did change any state variable

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

// in multiple inhertiance 
// Most Based Like to Most Derived
//Right to left - Depth First Manner
contract A{
    uint public a;
    constructor(){

ArslanKathia

//SPDX-License-Identifier: MIT
pragma solidity ^0.8;

contract A{
    uint public a;
    constructor(){
        a = 100;
    }

    function funA() public{

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract A{
    string public name;
    uint public age;
    constructor(string memory _name,uint _age){
        name = _name;
        age = _age;

ArslanKathia

//SPDX-License-Identifier: MIT
pragma solidity ^0.8;

contract A{
    event log(string text,uint age);
    
    function fun1() public virtual{
        emit log("A.fun1",21);
    }
    function fun2() public virtual{

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract Require{
    address public owner = msg.sender;
    uint public age = 25;
    //when require condition is false than execution stopped and previously set the state variable goes to reset state
    // and refund the gas fee.
    function CheckAge(uint _x) public{

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract RevertAssert{
    address public owner = msg.sender;
    uint public age = 25;
    
     function CheckAge(uint _x) public{
        age = age + 5;

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract modifiers{

    address public owner = msg.sender;
    uint public _xx = 10;

    //modifier is used to reuse the same code from the starting or ending of the function 

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8;

contract Payable{

    // address make it payable
    address payable public owner = payable(msg.sender);