final和const区别

final：修饰变量，初始化之后不可改变值

final name = 'zhangsan';

const：修饰常量

const name = 'zhangsan';

const常量值必须在编译期确定

  var zhangsan = 12;
  var lisi = 13;
  const sum = zhangsan + lisi; //error
  final sum = zhangsan + lisi; //ok