Example(2 6- abstract class Number PhoneCard extends PhoneCard long cardNumber; int password; String connectNumber; boolean connected; boolean performConnection(long cn,int pw) if (cn =cardNumber &pw =password) { connected true; return true; else return false; 返回
6-6 Programming in Java abstract class Number_PhoneCard extends PhoneCard { long cardNumber; int password; String connectNumber; boolean connected; boolean performConnection(long cn,int pw) { if (cn == cardNumber && pw == password) { connected = true; return true; } else return false; } } Example(2) 返回
二Xap② class magCard extends None Number PhoneCard { double balance; String usefulArea; boolean performDialO { if (balance 0.9) { balance -0.9; return true; else return fslase; Q} 返回
6-7 Programming in Java class magCard extends None_Number_PhoneCard { String usefulArea; boolean performDial() { if (balance > 0.9) { balance -= 0.9; return true; } else return fslase; } } Example(3) 返回 double balance;
二Xap② 6- class IC Card extends None Number PhoneCard boolean performDialO) { if (balance 0.5) { balance -0.9; return true; } else return false; 3 3 返回
6-8 Programming in Java class IC_Card extends None_Number_PhoneCard { boolean performDial() { if (balance > 0.5) { balance -= 0.9; return true; } else return false; } } Example(3) 返回
二xamp②(3 class IP Card extends Number PhoneCard Date expireDate; boolean performDialO { if (balance 0.3 &expireDate.after(new Date()) { balance -0.3; return true; else return false; 返回
6-9 Programming in Java class IP_Card extends Number_PhoneCard { Date expireDate; boolean performDial() { if (balance > 0.3 && expireDate.after(new Date())) { balance -= 0.3; return true; } else return false; } } Example(3) 返回
二Xap23 6 class D200 Card extends Number PhoneCard { double balance;//Number PhoneCard double balance; double additoryFee; boolean performDialO if (balance >(0.5+additoryFee)) { balance -=(0.5 additoryFee); return true; else reurn false; } 返回
6-10 Programming in Java class D200_Card extends Number_PhoneCard { double balance; double additoryFee; boolean performDial() { if (balance >(0.5+additoryFee)) { balance -= (0.5 + additoryFee); return true; } else reurn false; } } Example(3) 返回 double balance;//Number_PhoneCard