Are there null like thing in solidity

Question

    struct buyer{
       uint amount;
       Status status;
    }

    mapping(address=>buyer) public buyers;
    mapping(uint=>address) buyerIndex;
    uint publi         


        

Answer 1

There is nothing like null in solidity.

Just check for the length of the address:

if(buyers[msg.sender].length == 0){
    // do your thing
}

See also this answer on ethereum stack exchange.