What if Gas required in my program exceeds the limit of 3000000

Question

My code written in Remix IDE got created successfully but gives the following error:

Gas required exceeds limit: 3000000. An important gas estimation might also be the sign of a problem in the contract code. Please check loops and be sure you did not sent value to a non payable function

Do I need to improvise my code? Can anyone help me with this?

Following is my code:

pragma solidity ^0.4.16;

contract createNewToken {
    uint256 total_ether_to_send;
    address private owner;

    //constructor
    function createNewToken() public{
        owner = msg.sender;
    }

    // client request for tokens by sending ether.
    function requestForToken() public payable{
        address sender = msg.sender;
        uint value = msg.value;
        total_ether_to_send = value;
        require(sender.balance >= total_ether_to_send);
        owner.transfer(total_ether_to_send);

        total_ether_to_send = value / 2;
        require(owner.balance >= total_ether_to_send);
        sender.transfer(total_ether_to_send);
    } 
}

Answer 1

Going through your code, I noticed that  you don't have a fallback function in your contract to receive ether.

Also, your msg.value is already sent to your method, hence you don't need to check senders balance: require(sender.balance >= total_ether_to_send); .

See, what you're doing is you are trying to send 100% msg.value to owner and then send 50% of msg.value back to sender. Obviously, you cannot spend 150% of msg.value without any additional funds on your contract.

Following is an example:

function requestForToken() public payable{
    address sender = msg.sender;
    uint value = msg.value;
    total_ether_to_send = value / 2;
    require(this.balance >= total_ether_to_send);
    owner.transfer(total_ether_to_send);

    require(this.balance >= total_ether_to_send);
    sender.transfer(total_ether_to_send);
} 

function() payable {}