[solidity] instance(분신)-constructor/상속/overriding (feat.솔리디티깨부수기)

1. instance(분신만들기)-constructor생성자

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract A {
    string public name;
    uint256 public age;

    constructor(string memory _name, uint256 _age) {
        name = _name;
        age = _age;
    }
    function change(string memory _name, uint256 _age) public {
        name = _name;
        age = _age;
    }
}

contract B{
    A instance = new A("Alice", 20);
    
    function change(string memory _name, uint256 _age) public {
        instance.change(_name, _age);
    }

    function get() public view returns(string memory, uint256) {
        return (instance.name(), instance.age());
    }
}

 

 

2. 상속

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract Father {
    string public familyName = "kim";
    string public givenName = "go";
    uint256 public money = 100;

    constructor(string memory _givenName) public {
        givenName = _givenName;
    }

    function getFamilyName() view public returns(string memory) {
        return familyName;
    }
    function getGivenName() view public returns(string memory) {
        return givenName;
    }
    function getMoney() view public returns(uint256) {
        return money;
    }
}

contract Son is Father("James") {
    
}

 

 

3. overriding

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract Father {
    string public familyName = "kim";
    string public givenName = "go";
    uint256 public money = 100;

    constructor(string memory _givenName) public {
        givenName = _givenName;
    }

    function getFamilyName() view public returns(string memory) {
        return familyName;
    }
    function getGivenName() view public returns(string memory) {
        return givenName;
    }
    function getMoney() view public virtual returns(uint256) { //⭐️가져다 쓸 함수에 virtual써주기
        return money;
    }
}

contract Son is Father("James") {
    // constructor() Father("James"){
    // }

    uint256 public earning = 0;

    function work() public {
        earning += 100;
    }
    function getMoney() view override public returns(uint256){ //⭐️override 쓰고 사용하기
        return money + earning;
    }
}

 

 

4. 상속 2개받기

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract Father {
    uint256 public fatherMoney = 100;
    function getFatherName() public pure returns(string memory) {
        return "fafa";
    }
    function getMoney() public view virtual returns(uint256) {
        return fatherMoney;
    }
}

contract Mother {
    uint256 public motherMoney = 500;
    function getMotherName() public pure returns(string memory) {
        return "mama";
    }
    function getMoney() public view virtual returns(uint256) {
        return motherMoney;
    }
}
contract Son is Father,Mother {
    function getMoney() public view override(Father, Mother) returns(uint256) {
        return fatherMoney+motherMoney;
    }
}