// pragma solidity ^0.4.0;
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.4.16 <0.8.0;
contract FixArray{
    uint[5] arr;
    uint[3] arrInit = [1,2]; // 定义初始化
    uint[] arr3 = [1,2,3];
    constructor() public {
        arr[0] = 100;
        arr[1] = 200;
    }
    function getArray()public view returns(uint[5]){
        return arr;
    }
    function getInitArray() public view returns(uint[3]){
        return arrInit;
    }
    function getGrade() public view returns(uint){
        uint grade = 0;
        for(uint i = 0; i < arrInit.length; i++){
            grade += arrInit[i];
        }
        return grade;
    }
    function getLength() public view returns(uint arrlen, uint arrInitlen , uint arr3len){
        // changeLength 调用前 5 3 3
        // changeLength 调用后 5 3 10
        return (arr.length, arrInit.length, arr3.length);
    }
    function changeLength()public{
        // arrInit.length = 2;// 不可以
        // arr.length = 20;
        arr3.length = 10;
    }
    function add() public {
        // arr.push(1);
        // arrInit.push(1);
        arr3.push(1);
    }
}