ArslanKathia

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import "@openzeppelin/contracts/utils/cryptography/draft-EIP712.sol";

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
//import "@openzeppelin/contracts/token/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20Permit.sol";

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity >=0.7.0 <0.9.0;

contract CollegeData{

    struct Student{
        uint rollNo;
        string name;
        string class;

ArslanKathia

//SPDX-License-Identifier: MIT

pragma solidity >=0.8.2 < 0.9.0;

contract EtherGame{
    uint public targetAmount;
    address public winner;

    constructor(){
        targetAmount =  7 ether;

ArslanKathia

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 < 0.9.0;

contract CrowdFunder{
    //variables set by the creator
    address public creator;
    address payable public fundRecipient;
    uint public minimumToRaise;
    string campignUrl;

ArslanKathia

//SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 < 0.9.0;

contract Freelancer{
    address public owner;
    uint256 private coins;
    uint256 private cash;
    bytes32 private service;

ArslanKathia

//SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 < 0.9.0;

contract SimpleBank{

    mapping(address => uint) private balances;

    address public owner;

ArslanKathia

// Now, the basics of Solidity

// 1. DATA TYPES AND ASSOCIATED METHODS
// uint used for currency amount (there are no doubles
//  or floats) and for dates (in unix time)
uint x;

// int of 256 bits, cannot be changed after instantiation
int constant a = 8;
int256 constant a = 8; // same effect as line above, here the 256 is explicit

ArslanKathia

//SPDX-License-Identifier: GPL-3.0

pragma solidity >= 0.7.0 < 0.8.18;

contract Ballot{

    struct Voter{
        uint weight;
        bool voted;
        address delegate;

ArslanKathia

//SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.0;

contract Ownable{
    address public owner;

    event OwnershipTransferred(address indexed _previousOwner, address indexed newOnwer);
    modifier onlyOwner{
        require(owner == msg.sender,"Only Owner can access this");