Adding features to the ICO contract

So far, we have talked about creating a basic ICO contract. The crowdsale contract can also have additional features such as a sale duration or limiting the number of tokens sold. This helps in further automating the crowdsale process for efficient distribution. 

In this recipe, you will learn to limit the tokens sold and the time in which a sale can happen. We will extend the crowdsale contract created in the previous recipe to add these features.

Getting ready

You need to have a development environment that supports solidity programming and an Ethereum network to deploy and test your code. 

Since the contract extends the crowdSale contract created in the previous recipe, it is recommended to finish it before stepping through this recipe.

How to do it…

1. Contracts can have a cap to restrict the amount that can be raised through the crowdsale. Create a variable to store the cap restriction:

uint256public cap;

2. The value is assigned through the constructor. Add the...