constructor - Solidity 解析器错误 : Expected identifier but got '='

Question

为什么下面的代码包含错误( ParserError: Expected identifier but got '=' )。

contract Test {

    struct Box {
        uint size;
    }

    Box public box;
    box.size = 3;    //<-- error here

    constructor() public {
    }

}

如果我把 box.size = 3;进 constructor !

contract Test {

    struct Box {
        uint size;
    }

    Box public box;

    constructor() public {
        box.size = 3;
    }

}

Answer 1

语法不允许在契约(Contract)级别进行分配。但它允许声明状态变量和 these can contain an initializer .因此你可以用

Box public box = Box({ size: 3 });

或者

Box public box = Box(3);