Transfer and Approve of ERC20 tokens

[franco_villa_santana]

Using the Openzeppelin libraries, for example in a function to deposit tokens, I need to check if the contract is approved and the user has the tokens or does the Transfer function take care of that?

[Skyge]

Yeah, when you deposit tokens, you should approve at first, actually, it should be

token.approve(contract, approvalAmount);
contract.deposit(amount);

And in the function deposit(), it should call transferFrom().

[abcoathup]

Hi @franco_villa_santana,

You may want to look at the following examples:

• Example on how to use ERC20 token in another contract
• Example of withdrawing an ERC20 from another contract