Updating values in dynamic array - Solidity

Question

I need to add a number to existing value in array under index 'id'. I have the following code:

 contract Store {

  uint256[] public totalamt;

  function append(uint256 id,uint price) payable{

    totalamt[id] = totalamt[id] + price;

}

   }

Array is not initialized.Each time I need to update the array.Help will be appreciated :)

Answer 1

I think you're better off with a mapping. It does exactly what you want.

Here's how:

contract Store {

    mapping(uint256 => uint256) public totalamt;

    function append(uint256 id,uint price) payable public {

        totalamt[id] = totalamt[id] + price;

    }
}