Index

Chapter 8: Working With Structs and Arrays

Creating New Structs

Remember our Person struct in the previous example?

struct Person {
uint age;
string name;
}

Person[] public people;

Now we're going to learn how to create new Persons and add them to our peoplearray.

// create a New Person:
Person satoshi = Person(172, "Satoshi");

// Add that person to the Array:
people.push(satoshi);

We can also combine these together and do them in one line of code to keep things clean:

people.push(Person(16, "Vitalik"));

Note that array.push() adds something to the end of the array, so the elements are in the order we added them. See the following example:

uint[] numbers;
numbers.push(5);
numbers.push(10);
numbers.push(15);
// numbers is now equal to [5, 10, 15]

Put it to the test

Let's make our createZombie function do something!
1. Fill in the function body so it creates a new Zombie, and adds it to the zombiesarray. The name and dna for the new Zombie should come from the function arguments.
2. Let's do it in one line of code to keep things clean.

pragma solidity ^0.4.25;

contract ZombieFactory {

    uint dnaDigits = 16;
    uint dnaModulus = 10 ** dnaDigits;

    struct Zombie {
        string name;
        uint dna;
    }

    Zombie[] public zombies;

    function createZombie (string _name, uint _dna) {

        zombies.push(Zombie(_name, _dna));

    }

}