LEARN SOLIDITY LESSON 6: Require. Inheritance. Import Solidity

LEARN SOLIDITY LESSON

Require Solidity. Inheritance Solidity. Import Solidity

Require Solidity

For that we use require. require makes it so that the function will throw an error and stop executing if some condition is not true

function sayHiToBean(string memory _name) public returns (string memory) {  // Compares if _name equals "Bean". Throws an error and exits if no
  require(keccak256(abi.encodePacked(_name)) == keccak256(abi.encodePacked("Bean")));
  // If it's true, proceed with the function:
  return "Hi!";
}

Inheritance Solidity

This can be used for logical inheritance (such as with a subclass, a Cat is an Animal). But it can also be used simply for organizing your code by grouping similar logic together into different contracts.

contract Cat {
  function catchphrase() public returns (string memory) {
    return "So Wow CryptoCat";
  }
}
contract BabyCat is Cat {
  function anotherCatchphrase() public returns (string memory) {
    return "Such Moon BabyCat";
  }
}

Import Solidity

When you have multiple files and you want to import one file into another, Solidity uses the import keyword:

pragma solidity >=0.5.0 <0.6.0;import "./catHelp.sol";
contract CatFeeding is CatFactory {

}