Loop increments

#solidity #gasoptimization #bestpractice

This is a very simple technique which many of us might be using without knowing it's gas efficient.

Consider the following contracts:

contract Inc1{
    uint[] public arr = [0,1,2,3,4,5,6,7,8,9,10];
    uint total;

    function something() external {
        uint sum;
        uint[] memory _arr = arr;
        for (uint i; i < _arr.length; i += 1) {
            sum += _arr[i];
        }
        total = sum;
    }
}

contract Inc2{
    uint[] public arr = [0,1,2,3,4,5,6,7,8,9,10];
    uint total;

    function something() external {
        uint sum;
        uint[] memory _arr = arr;
        for (uint i; i < _arr.length; i++) {
            sum += _arr[i];
        }
        total = sum;
    }
}

Both the contracts have function something which iterates through the array to sum all the elements. But the difference is in the increment style of loops. Inc1 has i +=1 while Inc2 has i++

Inc1

Inc2

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