solidity向合约内部转账

pragma solidity ^0.4.24;

contract Foo01{
    
    address public owner;
    uint256 public  a;
    address public caller;
    
    
    constructor() public payable{
        owner=msg.sender;
    }
    
    function setValue(uint256 input) public{
        a=input;
        caller=msg.sender;
    }
  
    
}