條件控制

if 語句

// if 判斷
var number = 1;
var isMax = true;
if (number > 0) {
  isMax = true;
} else {
  isMax = false;
}

for 語句

// for 循環(huán)
var list = [0, "val1", "val2", true, false];
for (var index = 0; index < list.length; index++) {
  print(list[index]);
}
for (var item in list) {
  print(item);
}

while 語句

// while 循環(huán)
var index = 0;
while (index < 5) {
  index++;
  print(index);
}
do {
  index--;
  print(index);
} while (index > 0);

break 和 continue

// break 和 continue
var list2 = [0, "val1", "val2", true, false];
for (var index = 0; index < list2.length; index++) {
  if (index == 1) {
    // 跳出當前循環(huán)體
    break;
  }
  print(list[index]);
}
for (var index = 0; index < list2.length; index++) {
  if (index == 1) {
    // 跳出本次循環(huán)條件，繼續(xù)執(zhí)行其余循環(huán)
    continue;
  }
  print(list[index]);
}

switch case 語句

// switch case 語句
// 比較類型：num，String，編譯器常量，對象，枚舉
var name = "Dart";
switch (name) {
  case "Dart":
    print("It is Dart");
    break;
  case "Java":
    print("It is Java");
    break;
  default:
    print("It is None");
    break;
}

// 使用 continue 跳轉(zhuǎn)標簽
switch (name) {
  Test1: // 給分支添加標簽
  case "Dart":
    print("It is Dart");
    // 跳轉(zhuǎn)到指定標簽；會執(zhí)行標簽的分支
    continue Test3;
  Test2:
  case "Java":
    print("It is Java");
    break;
  Test3:
  default:
    print("It is None");
    break;
}