Mastering Blockchain Programming with Solidity

Compiling contracts

To compile the project, execute the following command in the Truffle project:

$ truffle compile

As you can see from the following the output of the truffle compile command, it compiles all the contracts, including the OpenZeppelin contracts that we are using in the project:

The output of the Truffle compile command

As you can see in the preceding screenshot, the truffle compile command returned compilation warnings. This warning is present in the Crowdsale.sol contract of the OpenZeppelin library. As per the warning, it is suggesting the use of the pure keyword for the _preValidatePurchase() function. However, the function ...