Java基本基本寫作入門20070417

public class Account {
 private double balance;//double是浮點數的型態, private是私有的
 public Account(double money)//建構式初始化--收一筆錢當作開戶頭的金額
 {
  if(money >0.0)
    balance=money;//判斷錢是否負數,
 }
 public void credit(double amount)//void代表無回傳值
 {
  balance=balance+amount;//balance是原本存款的錢
 }
 public double getBalance()
 {
  return balance;//把balance的錢回傳回去
 }
}

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import java.util.Scanner;
public class AccountTest {
 public static void main(String[] args) {
  Account A1=new Account(100);
  Account A2=new Account(-100);
  System.out.printf("目前帳戶的餘額為%.2f\n",A1.getBalance());//%f為浮點數,.2f為取小數點後2位
        System.out.printf("目前A2帳戶餘額為%.2f\n",A2.getBalance());
       
        System.out.print("請問A1要存多少錢:");
        Scanner input=new Scanner (System.in);
        double deposit;
        deposit=input.nextDouble();
        A1.credit(deposit);//呼叫credit存多少錢
       
        System.out.print("請問A2要存多少錢:");
        deposit=input.nextDouble();
        A2.credit(deposit);
       
        System.out.printf("目前帳戶的餘額為%f\n",A1.getBalance());
        System.out.printf("目前A2帳戶餘額為%f\n",A2.getBalance());
 }

}

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import java.util.Scanner;
public class GradeBook {
 public void ClassAverage()//課程平均
 {
  int count=1,grade, sum=0, average;//int grade, int sum=0, int average 寫成一行;
  Scanner input=new Scanner(System.in);

  while(count<=10);//要成績10次, count從0開始就要<10...
  {
   System.out.print("請輸入成績(0~100)");
   grade=input.nextInt();
   sum=sum+grade;//看筆記本, sum為總成績
   count=count+1;//每收成績一次後加1
  }

  average=sum/10;
  System.out.printf("平均為%d",average);
 }

}

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public class GradeBookTest {
 public static void main(String[] args) {
  GradeBook my=new GradeBook();
  my.ClassAverage();
 }

}