藏身时间类中的妖孽-阿里云开发者社区

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

藏身时间类中的妖孽

热门文章

最新文章

相关电子书