Dart 运算符、条件表达式、Dart类型转换

//1.Dart 运算符
//算术运算符    +   -     *    /     ~/(取整)    %
//关系运算符    ==    !=    >    <    >=   <=
//逻辑运算符    ！  &&   ||
//赋值运算符    =  ??=   +=   -=   *=   /=  %=  ~/=

void main(){

  int a = 9;
  int b = 2;
  print(a%b);  //1
  print(a~/b); //4

  int c;
  print(c??=5);//如果c为null的话，把5赋值给c


  //类型转换
  String str = "123";
  //String 转 int
  var myNum = int.parse(str);
  print(myNum);


  //判断字符串是否为空
  if(str.isEmpty){
    print("str为空");
  }else{
    print("str不为空");
  }

  //int类型转换为String类型
  var number = 14;
  var s = number.toString();
  print(s);



 
  try{
  //String 转 double
  String s = "12.5";
  var nums = double.parse(s);
  print(nums);
  }catch(err){
    print(err);
  }
}