藏身时间类中的妖孽

来源:互联网 发布:openwrt mac 编辑:程序博客网 时间:2024/03/29 02:35

下面的代码,是一位同学为《初识对象》中的项目3时间类写的。但错误有点诡异,他在QQ群中求助。

#include <iostream>using namespace std;class Time{public:    void set_time();    void show_time();    void add_sec(int);    void add_minute(int);    void add_hour(int);    void add_a_sec()    {        sec=sec+1;        if(sec==60)            {             sec=0;             minute=minute+1;             if(minute==60)             {                 minute=0;                 hour=hour+1;             }    }    void add_a_minute()    {        minute=minute+1;        if(minute==60)             {                 minute=0;                 hour=hour+1;             }    }    void add_an_hour()    {        hour=hour+1;    }private:    bool is_time(int, int, int);   //这个成员函数设置为私有的,是合适的,请品味    int hour;    int minute;    int sec;};void Time::set_time(){    char c1,c2;    cout<<"请输入时间(格式hh:mm:ss)";    while(1)    {    cin>>hour>>c1>>minute>>c2>>sec;        if(c1!=':'||c2!=':')            cout<<"格式不正确,请重新输入"<<endl;        else if (!is_time(hour,minute,sec))            cout<<"时间非法,请重新输入"<<endl;        else            break;    }}void Time::show_time(){    cout<<hour<<":"<<minute<<":"<<sec<<endl;}bool Time::is_time(int h,int m, int s){    if (h<0 ||h>24 || m<0 ||m>60 || s<0 ||s>60)        return false;    return true;}void Time::add_sec(int adds){    sec=sec+adds;        while(sec>=60)        {           sec=sec-60;           minute=minute+1;           if(minute==60)           {               minute=0;               hour=hour+1;           }        }}void Time::add_minute(int addm){        minute=minute+addm;        while(minute>=60)        {            minute=minute-60;            hour=hour+1;        }}void Time::add_hour(int addh){        hour=hour+addh;}int main( ){    Time t1;    int adds,addm,addh;    cout<<"请输入要增加的秒,分,小时"<<endl;    cin>>adds>>addm>>addh;    t1.set_time( );    T1.show_time( );    t1.add_a_sec();    t1.add_a_minute();    t1.add_an_hour();    t1.add_sec(adds);    t1.add_minute(adds);    t1.add_hour(addh);    return 0;}
读者朋友,你编译一下试试?

我在CodeBlocks中编译,提示一大堆:

||=== Build: Debug in example (compiler: GNU GCC Compiler) ===|D:\CPP\codeBlock\example\main.cpp|43|error: extra qualification 'Time::' on member 'set_time' [-fpermissive]|D:\CPP\codeBlock\example\main.cpp|43|error: 'void Time::set_time()' cannot be overloaded|D:\CPP\codeBlock\example\main.cpp|6|error: with 'void Time::set_time()'|D:\CPP\codeBlock\example\main.cpp|57|error: extra qualification 'Time::' on member 'show_time' [-fpermissive]|D:\CPP\codeBlock\example\main.cpp|57|error: 'void Time::show_time()' cannot be overloaded|D:\CPP\codeBlock\example\main.cpp|7|error: with 'void Time::show_time()'|D:\CPP\codeBlock\example\main.cpp|61|error: extra qualification 'Time::' on member 'is_time' [-fpermissive]|D:\CPP\codeBlock\example\main.cpp|67|error: extra qualification 'Time::' on member 'add_sec' [-fpermissive]|D:\CPP\codeBlock\example\main.cpp|67|error: 'void Time::add_sec(int)' cannot be overloaded|D:\CPP\codeBlock\example\main.cpp|8|error: with 'void Time::add_sec(int)'|D:\CPP\codeBlock\example\main.cpp|81|error: extra qualification 'Time::' on member 'add_minute' [-fpermissive]|D:\CPP\codeBlock\example\main.cpp|81|error: 'void Time::add_minute(int)' cannot be overloaded|D:\CPP\codeBlock\example\main.cpp|9|error: with 'void Time::add_minute(int)'|D:\CPP\codeBlock\example\main.cpp|90|error: extra qualification 'Time::' on member 'add_hour' [-fpermissive]|D:\CPP\codeBlock\example\main.cpp|90|error: 'void Time::add_hour(int)' cannot be overloaded|D:\CPP\codeBlock\example\main.cpp|10|error: with 'void Time::add_hour(int)'|D:\CPP\codeBlock\example\main.cpp|109|error: expected '}' at end of input|D:\CPP\codeBlock\example\main.cpp||In member function 'void Time::add_a_sec()':|D:\CPP\codeBlock\example\main.cpp|13|error: 'sec' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|17|error: 'minute' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|21|error: 'hour' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|25|error: a function-definition is not allowed here before '{' token|D:\CPP\codeBlock\example\main.cpp|42|error: expected '}' at end of input|D:\CPP\codeBlock\example\main.cpp||In member function 'void Time::set_time()':|D:\CPP\codeBlock\example\main.cpp|48|error: 'hour' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|48|error: 'minute' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|48|error: 'sec' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp||In member function 'void Time::show_time()':|D:\CPP\codeBlock\example\main.cpp|59|error: 'hour' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|59|error: 'minute' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|59|error: 'sec' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp||In member function 'void Time::add_sec(int)':|D:\CPP\codeBlock\example\main.cpp|69|error: 'sec' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|73|error: 'minute' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|77|error: 'hour' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp||In member function 'void Time::add_minute(int)':|D:\CPP\codeBlock\example\main.cpp|83|error: 'minute' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|87|error: 'hour' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp||In member function 'void Time::add_hour(int)':|D:\CPP\codeBlock\example\main.cpp|92|error: 'hour' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp||In member function 'int Time::main()':|D:\CPP\codeBlock\example\main.cpp|101|error: 'T1' was not declared in this scope|D:\CPP\codeBlock\example\main.cpp|103|error: 'class Time' has no member named 'add_a_minute'|D:\CPP\codeBlock\example\main.cpp|104|error: 'class Time' has no member named 'add_an_hour'|D:\CPP\codeBlock\example\main.cpp|109|error: expected unqualified-id at end of input|||=== Build failed: 38 error(s), 0 warning(s) (0 minute(s), 1 second(s)) ===|

第一个提示“extra qualification 'Time::' on member 'set_time'”,说Time::多余,类外定义成员函数,不多余啊!
第二个提示“ 'void Time::set_time()' cannot be overloaded”,Time::set_time()不能被重载。
我大概知道怎么回事了。
用resource code formatter整理程序的格式,缩进发生变化,妖孽立刻现身。


下面是我和学生在QQ群中的对话,读者如果没有找出错误,不妨边看边试,按我的提示,自己找出问题来。

贺老师 2015-3-21 18:54:18
在Code::Blocks中,你整理一下格式,你会知道这个错有多么低级。然后回头再看这些错误提示,可以引出不少有价值的东西来。

贺老师 2015-3-21 18:55:28
其他同学,也可以从XX的低级错误中学到不少,试试吧。

学生 2015-3-21 18:57:37
糗大了

贺老师 2015-3-21 18:59:26
这样的错误,在学习过程中,价值连城!你经过了这样的错误,你就拥有了特别的财富。

学生 2015-3-21 19:00:37
 还是有一点不大明白

贺老师 2015-3-21 19:01:13
重排版了吗?

学生 2015-3-21 19:01:25
排了

贺老师 2015-3-21 19:01:34
你能确认void Time::set_time()是在类外了吗?

学生 2015-3-21 19:02:37
嗯  类内定义  类外写函数

贺老师 2015-3-21 19:03:06
如果类外定义,这个函数该顶头才是,

贺老师 2015-3-21 19:03:19
类内定义,才会缩进去。

贺老师 2015-3-21 19:03:46
你类内声明,类内定义。

贺老师 2015-3-21 19:04:22
这就重复了。

贺老师 2015-3-21 19:07:50
发现了吗?要不要再给点线索?

学生 2015-3-21 19:08:34
在给点吧 

贺老师 2015-3-21 19:09:07
你看类内定义的void add_a_sec(),在哪儿结束的?

学生 2015-3-21 19:10:09
  落了一个括号

贺老师 2015-3-21 19:10:26
手边有砖吗?

学生 2015-3-21 19:10:54
不是 是括号括错了   我去买块豆腐砖

学生 2015-3-21 19:11:45
谢谢贺老    

贺老师 2015-3-21 19:11:48
没砖为师就放心了。不必拍,我怕豆腐疼。学习过程中,很正常。

贺老师 2015-3-21 19:12:40
以后错误莫名其妙时,可以排版一下。若缩进不正常,问题一下就出来了。这也是讲究规范的价值。

学生 2015-3-21 19:13:00
恩恩 学到了





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