| 发表于:2007-05-22 09:32:14 楼主 |
import java.awt.*; import java.awt.event.*; public class usephone { public static void main(string arg[]) { phonecard mycard=new phonecard(12345678.1234.50.0, "300 "); system.out.printin(mycard.tostring( )); } } class phonecard { long cardnumber; private int password; double balance; string connnectnumber; boolean connected; phonecard(long cn,it pw,double b,string s) { cardnumber = cn; password = pw; if(b> 0) balance = b; else system.exit(1); connectnumber = s; connected = false; } boolean performconnection(long cn,int pw) { if(cn == cardnumber&&pw == password ) { connected = true; return true } else { connected = false; return false; } } double getbalance { if(connected) return balance; else return -1; } void performdial() { if(connected) balance -= 0.5; } public string tostring() { string s = "电话卡接入号码: "+connectnumber+ "\n电话卡卡号: "+cardnumber+ "\n电话卡密码: "+password+ "\n剩余金额: "+balance; if(connected) return (s+ "\n电话已接通: "); else return (s+ "\n电话未接通: "); } } 在java程序中,程序是如何执行的?换句话说就是,java执行的流程? 在执行到main方法的时候,是不是也象c语言那样遇到需要的函数的时候就进行调用与之相对应的函数,如本程序中的main方法中,程序执行到phonecard mycard=new phonecard(12345678.1234.50.0, "300 ")这条语句的时候,是不是调用了phonecard类中的phonecard()方法?然后执行到system.out.printin(mycard.tostring( )) 是不是也和phonecard()方法一样呢?还有performconnection(long cn,int pw),该方法在main方法中未见调用其,而在接着的phonecard中,也是定义了相关的信息,也未见有调用的。 |
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