Dart基础

main(List args) {
String name = “why”;

var age = 20;

age = 30;

final height = 1.88;

const address = “广州市”;

// const 必须赋值（编译期间确定一个值），final可以通过（运行期间确定一个值）

const p1 = Person(“why”);

const p2 = Person(“why”);

print(identical(p1, p2));
}

class Person {
final String name = “”;
const Person(String name);
}

字符串

var name = “why”;
var age = 19;
var height = 1.88;

var message = “my name is ${height}”;

集合
main(List args) {
// List
var names = [“abc”, “cba”, “nba”];
// Set
var movies = {“流浪地球”, “大话西游”};
// Map
var info = {“name”: “why”, “age”: 18};
}

函数

main(List args) {
print(sun(2, 4));
}

int sun(int num1, int num2) {
return num1 + num2;
}

函数可选参数

main(List args) {}

//位置可选参数
void sayHello(String name, [int age, double height]) {}

void sayHello2(String name, {int age = 2, double height}) {}

函数

main(List args) {
test(bar);

test(() {
print(“ssssssssss”);
return 10;
});
// 箭头函数
test(() => print(“ssssssssssssssssssss”));
}

void test(Function foo) {
var result = foo();
}

void bar() {
print(“ssssssssss”);
}

函数类型定义

main(List args) {
test((num1, num2) {
return num1 + num2;
});

var d = demo();
print(d(20, 30));
}

typedef Calculate = int Function(int num1, int num2);

void test(Calculate calc) {
calc(20, 30);
}

Calculate demo() {
return (int num1, int num2) {
return num1 * num2;
};
}