How do we know which native or non-native token will be transferred when we call transfer()/send(), or use balanceOf inside token contract?

Question

Let's say we have a non-native contract. Whenever we call transfer()/send() or directly manipulate via balanceOf, how do we know which token (either native or non-native token) will be transferred?

I came across this from looking at this scam contract's decompiled source code. Obviously I didn't see any import of IERC20 or anything, or decompilation probably won't include them ?

Such decompiled code works with STPT token, and it's on BSC network. As I looked in the code, and transactions, I came to conclusion that balanceOf works against STPT token. But how can we know this when looking at the code alone without checking elsewhere?

As we have multiple ways to transfer as follows

• payable(addr).transfer(amount) - I knew this from here that this is meant to transfer native token
• transfer() and send() - I believe the developer needs to know such that the variable that calls this method needs to be based upon IERC20 or others ?
• balanceOf() - I'm not sure about this...

Please feel free to correct me, go in depths or link me articles to read more on this stuff. Thank you very much in advance.

Answer 1

The methods (payable address).transfer() or (payable address).send() inside a smart contract is about transfering the native coin of the blockchain from the smart contract to the defined (payable address). In Ethereum, it will transfer Ether. In BsC, it will transfer BNB.