C++ incomprehensible compiler errors

Question

I got a pretty simple task to do. Write a class that defines time. For some reason, in one of the functions I get an error, that I do not understand.
I searched for a solution with no success, so in the end I decided post it here.

time.h

class time
{
private:
    int _hours;
    int _minutes;
    float _seconds;
    bool checkHours(int hours);
    bool checkMinutes(int minutes);
    bool checkSeconds(float seconds);

public:

time(int hours=0, int minutes=0, float seconds=0);
time(const time & tm);
~time();


void hours(int hours);
int  hours() const;
void minutes(int minutes);
int  minutes() const;
void seconds(float seconds);
float  seconds() const;


void operator=(time tm);
bool operator==(time tm);


void print();
time getTimeFromUser();
float getTimeAsFractionOfTheDay(time tm);

};

and time.cpp

#include <iostream>
#include "time.h"

bool time::checkHours(int hours)
{
    return hours>=0 && hours<24;
}
bool time::checkMinutes(int MS)
{
    return MS>=0 && MS<60;
}
bool time::checkSeconds(float MS)
{
    return MS>=0 && MS<60;
}

//constractors
time::time(int hours, int minutes, float seconds)
{
    if(checkHours(hours) && checkMinutes(minutes) && checkSeconds(seconds))
    {
        _hours=hours;
        _minutes=minutes;
        _seconds=seconds;
    }
    else
    {
        cout<<"Error"<<endl; _hours=-1; _minutes=-1; _seconds=-1;
    }
}
time::time(const time & tm)
{
    _seconds = tm.seconds();
    _hours = tm.hours();
    _minutes=tm.minutes();
}
time::~time()
{
}

//get-set functions
void time::hours(int hours)
{
    _hours=hours;
}
int  time::hours() const
{
    return _hours;
}
void time::minutes(int minutes)
{
    _minutes=minutes;
}
int  time::minutes() const
{
    return _minutes;
}
void time::seconds(float seconds)
{
    _seconds = seconds;
}

float  time::seconds() const
{
    return _seconds;
}

//operators
void time::operator=(time tm)
{

    _hours=tm.hours();
    _minutes=tm.minutes();
    _seconds=tm.seconds();

}
bool time::operator==(time tm)
{
    return _hours=tm.hours() && _minutes==tm.minutes() && _seconds==tm.seconds();
}

//some function
void time::print()
{
    cout<<" "<<_hours<<":"<<_minutes<<":"<<_seconds<<" "<<endl;
}

time time::getTimeFromUser()
{
    time newTime;
    int userhours=-1;
    int userminutes=-1;
    float userseconds=-1;
    while (!checkHours(userhours))
    {
        cout<<"enter hours"<<endl;
        cin>>userhours;
        if(!checkHours(userhours))
        {
            cout<<"Error try again"<<endl;
        }
    }

    while (!checkMinutes(userminutes))
    {
        cout<<"enter minutes"<<endl;
        cin>>userminutes;
        if(!checkMinutes(userminutes))
        {
            cout<<"Error try again"<<endl;
        }
    }

    while (!checkSeconds(userseconds))
    {
        cout<<"enter Seconds"<<endl;
        cin>>userseconds;
        if(!checkSeconds(userseconds))
        {
            cout<<"Error try again"<<endl;
        }
    }

    newTime.seconds(userseconds);
    newTime.hours(userhours);
    newTime.minutes(userminutes);

    return newTime;
}


float time::getTimeAsFractionOfTheDay(time tm)
{

    return 0.0;
}

And i got those errors

I don't understand what I did wrong. I think it's something stupid but I can't find it.

Answer 1

As it turns out, you are the victim of a subtle bug.

time is a function declared in the system header time.h, which is getting included in your program via iostream. When you declare time time::getTimeFromUser(), the compiler sees the return value and thinks you mean the function time!

clang makes this obvious with its error:

time.cpp:122:1: error: must use 'class' tag to refer to type 'time' in this scope
time time::getTimeFromUser()
^
class 
/usr/include/time.h:133:8: note: class 'time' is hidden by a non-type declaration of 'time' here
time_t time(time_t *);
       ^

The fix is to define that particular function like this:

class time time::getTimeFromUser() {
    ...
}

Or, if using C++11,

auto time::getTimeFromUser() -> time {
    ...
}