wallet.sol

pragma solidity 0.5.1;

contract MyContract
{
    mapping(address=>uint256)public balances;
    
    event Purchase(
        address indexed _buyer,
        uint256 _amount);
    
    
    address payable wallet;
    
    constructor (address payable  _wallet) public
    {
        wallet=_wallet;
    }
    
    
    function() external payable
    {
        buyToken();
    }
    
    
    function buyToken() public payable
    {
        //buy a token 
        balances[msg.sender]+=1;
        
        //send ether to wallet
        wallet.transfer(msg.value);
        
        emit Purchase(msg.sender,1);
        
        
    }
}