网友您好, 请在下方输入框内输入要搜索的题目:
题目内容
(请给出正确答案)
toString()的作用是()。
A.将任意类型的数据转换为布尔类型
B.将任意类型的数据转换为空值类型
C.将任意类型的数据转换为数字类型
D.将任意类型的数据转换为字符串类型
参考答案和解析
将任意类型的数据转换为字符串类型
更多 “toString()的作用是()。A.将任意类型的数据转换为布尔类型B.将任意类型的数据转换为空值类型C.将任意类型的数据转换为数字类型D.将任意类型的数据转换为字符串类型” 相关考题
考题
阅读下列Java程序和程序说明,将应填入(n)处的字句写在对应栏内。【说明】下面的程序先构造Point类,再顺序构造Ball类。由于在类Ball中不能直接存取类Point中的xCoordinate及yCoordinate属性值,Ball中的toString方法调用Point类中的toString方法输出中心点的值。在MovingBall类的toString方法中,super.toString调用父类Ball的toString方法输出类Ball中声明的属性值。public class Point{private double xCoordinate;private double yCoordinate;public Point 0 }public Point(ouble x, double y){xCoordinate = x;yCoordinate = y;}public String toString(){return "( + Double.toString(Coordinate)+ ","+ Double.toString(Coordinate) + ");}//other methods}public class Ball{(1); //中心点private double radius; //半径private String colour; ///颜色public Ball() { }public Ball(double xValue, double yValue, double r)// 具有中心点及半径的构造方法{center=(2);//调用类Point 中的构造方法radius = r;}public Ball(double xValue, double yValue, double r, String c)// 具有中心点、半径及颜色的构造方法{(3);//调用3个参数的构造方法colour = c;}public String toString(){return "A ball with center" + center, toString() + ", radius"+ Double.toString(radius) + ", colour" + colour;}//other methods}public class MovingBall. (4){private double speed;public MovingBall() { }public MovingBall(double xValue, double yValue, double r, String e, double s){(5);// 调用父类Ball中具有4个参数的构造方法speed = s;}public String toString( ){ return super, toString( ) + ", speed "+ Double.toString(speed); }//other methods}public class Tester{public static void main(String args[]){MovingBall mb = new MovingBall(10,20,40,"green",25);System.out.println(mb);}}
考题
你正在创建一个Web窗体。你写了如下的代码段去创建一个 SqlCommand对象:现在,你需要显示Customers表中客户的数量。下面那两个代码段能达到此目的?()
A. object customerCount = cmd.ExecuteScalar(); lblCompanyName.Text =customerCount.ToString();B. int customerCount = cmd.ExecuteNonQuery(); lblCompanyName.Text =customerCount.ToString();C. SqlDataReader dr = cmd.ExecuteReader(); dr.Read(); lblCompanyName.Text =dr[0].ToString();D. SqlDataReader dr = cmd.ExecuteReader(); dr.Read(); lblCompanyName.Text = dr.ToString();
考题
classSuper{publicIntegergetLenght(){returnnewInteger(4);}}publicclassSubextendsSuper{publicLongGetLenght(){returnnewLong(5);}publicstaticvoidmain(String[]args){Supersooper=newSuper();Subsub=newSub();System.out.println(sooper.getLenght().toString()+,”+sub.getLenght().toString());}}Whatistheoutput?()A.4,4B.4,5C.5,4D.5,5E.Compilationfails.
考题
阅读以下函数说明和Java代码,将应填入(n)处的字句写在对应栏内。【说明】下面的程序先构造Point类,再顺序构造Ball类。由于在类Ball中不能直接存取类Point中的xCoordinate及yCoordinate属性值,Ball中的toString方法调用Point类中的toStrinS方法输出中心点的值。在MovingBsll类的toString方法中,super.toString调用父类Ball的toString方法输出类Ball中声明的属性值。【Java代码】//Point.java文件public class Point{private double xCoordinate;private double yCoordinate;public Point(){}public Point(double x,double y){xCoordinate=x;yCoordinate=y;}public String toStrthg(){return"("+Double.toString(xCoordinate)+","+Double.toString(yCoordinate)+")";}//other methods}//Ball.java文件public class Ball{private (1);//中心点private double radius;//半径private String color;//颜色public Ball(){}public Ball(double xValue, double yValue, double r){//具有中心点及其半径的构造方法center=(2);//调用类Point中的构造方法radius=r;}public Ball(double xValue, double yValue, double r, String c){//具有中心点、半径和颜色的构造方法(3);//调用3个参数的构造方法color=c;}public String toString(){return "A ball with center"+center.toString()+",radius "+Double.toString(radius)+",color"+color;}//other methods}class MovingBall (4) {private double speed;public MovingBall(){}public MoyingBall(double xValue, double yValue, double r, String c, double s){(5);//调用父类Ball中具有4个参数的构造方法speed=s;}public String toString(){return super.toString()+",speed"+Double.toString(speed);}//other methods}public class test{public static void main(String args[]){MovingBall mb=new MovingBall(10,20,40,"green",25);System.out.println(mb);}}
考题
下面这段代码会产生( )个String对象。Strings1="hello";Strings2=s1.substring(2,3);Strings3=s1.toString();Strings4=newStringBuffer(s1).toString();A、1B、2C、3D、4
考题
以下程序能顺利通过编译: public class am_I_right { public static void main(String args[]) { this.toString(); } String toString() { retur。()
此题为判断题(对,错)。
考题
以下语句能顺利通过编译: class test { static void sayHello() { this.toString(); } public String toString() { retur。()
此题为判断题(对,错)。
考题
以下程序能顺利通过编译: class student { String sno,sname; static void output() { this.toString(); } String toString() { retur。()
此题为判断题(对,错)。
考题
class A { public String toString () { return “4”; } } class B extends A { 8. public String toString () { return super.toString() + “3”; } } public class Test { public static void main(Stringargs) { System.out.printIn(new B()); } } What is the result?() A、 Compilation succeeds and 4 is printed.B、 Compilation succeeds and 43 is printed.C、 An error on line 9 causes compilation to fail.D、 An error on line 14 causes compilation to fail.E、 Compilation succeeds but an exception is thrown at line 9.
考题
You are creating a Web Form. You write the following code segment to create a SqlCommand object.Dim conn As SqlConnection = New SqlConnection(connString)conn.Open( )Dim cmd As SqlCommand = conn.CreateCommand( )cmd.CommandText = "select count(*) from Customers"You need to display the number of customers in the Customers table. Which two code segments can you use to achieve this goal?()A、Dim customerCount As Object = cmd.ExecuteScalar()lblCompanyName.Text = customerCount.ToString()B、Dim customerCount As Integer = cmd.ExecuteNonQuery()lblCompanyName.Text = customerCount.ToString()C、Dim dr As SqlDataReader = cmd.ExecuteReader()dr.Read()lblCompanyName.Text = dr(0).ToString()D、Dim dr As SqlDataReader = cmd.ExecuteReader()dr.Read()lblCompanyName.Text = dr.ToString()
考题
填空题已知sb为 StringBuffer 的一个实例,且 sb.toString() 的值为 "abcde ", 则执行sb. reverse(),sb.toString()的值为()
考题
单选题class A { public String toString () { return “4”; } } class B extends A { 8. public String toString () { return super.toString() + “3”; } } public class Test { public static void main(Stringargs) { System.out.printIn(new B()); } } What is the result?()A
Compilation succeeds and 4 is printed.B
Compilation succeeds and 43 is printed.C
An error on line 9 causes compilation to fail.D
An error on line 14 causes compilation to fail.E
Compilation succeeds but an exception is thrown at line 9.
考题
判断题String s = (Double.valueOf("3.1415926")).toString()。A
对B
错
热门标签
最新试卷
![瑞牛题库 章节练习 历年真题 模拟试卷](http://assets.51tk.com/51_sidebar_right_index.jpg)