Undefined Reference to Time::Time(int,int,int)

Question

An error appeared while I was testing the driver code. The compiler raised such an error:

undefined reference to Time::Time(int, int, int)

AND

undefined reference to Time::setTime(int, int, int)

Why did the Code::Blocks IDE raise this error? Is it due to the main or any declaration or definition errors? Please point out my error.

TIME.H

# ifndef TIME1_H
# define TIME1_H

class Time
{
public:
    Time(int, int, int); // Default constructor
    void setTime(int, int, int); // Set hour, minute, second
    void printMilitary();
    void printStandard();

private:
    int hour;
    int minute;
    int second;

};
# endif

TIME.CPP

# include <iostream>
# include "TIME.H"
using namespace std;

// Implementing the functions

void Time::setTime(int hour, int minute, int second)
{
    setTime(hour, minute, second);
}

void Time::printMilitary()
{
    if(hour >= 1200 && hour <= 2359)
    {
        hour-1200;
        cout << hour << ":" << minute;
    }

    if(hour < 1200 && hour >= 100)
    {
        cout << hour << ":" << minute << ":" << second << " AM";
    }
    else
    {
         cout << hour << ":" << minute << ":" << second;
    }
}

void Time::printStandard()
{
    if(hour)
    {
        cout << hour << ":" << minute << ":" << second;
    {
    }
}

MAIN.CPP

# include <iostream>
# include "TIME.H"
using namespace std;

int main()
{
    Time a(0, 0, 0);
    a.setTime(12, 23, 18);
    return 0;
}

Are there any links to help?

When I tried the working demo posted by @Annop Raya, everything was fine when I ran the code. But when I try this code in Code::Blocks, it raised a few errors at the implementation file. The errors are shown below:

Line 6

error: 'Time' does not name a type; did you mean 'time'?

Line 11

error: 'Time' has not been declared

Line 17

error: 'Time' has not been declared

Line 17

In function 'void printMilitary()':

Line 19

'hour' was not declared in this scope

All the private member variables gets the same error, what's wrong?

In the main file, the compiler still returns the same error, so is there a solution for this?

Well, `#include time.h` in your `main.cpp` should do the trick — mutantkeyboard, Jun 21 '22 at 09:36
ot: comments are liars. `// default constructor` is not a default constructor. — 463035818_is_not_an_ai, Jun 21 '22 at 09:37
@YCS You should (and usually need to) define everything you declare. — user17732522, Jun 21 '22 at 09:40
Also since linker complains: `undefined reference to Time::setTime(int, int, int)` apparently your build process is wrong. So not only missing implementation of `Time:Time` is problem here. And this nasty infinitive recursion. — Marek R, Jun 21 '22 at 09:45
and once you fixed the linker errors you will have an issue with infinite recursion because `setTime` is calling `setTime` is calling `setTime` is calling .... without end. — 463035818_is_not_an_ai, Jun 21 '22 at 09:46
You are definitively not compiling `TIME.CPP` at all. It would otherwise produce error messages, since you have mismatched braces. Even if you get it to compile it will not behave correctly. There are multiple problems with the code. For another example the line `hour-1200;` doesn't do anything. — user17732522, Jun 21 '22 at 09:47
@463035818_is_not_a_number I know that this would happen, but I do not have the solution. — CPP_is_no_STANDARD, Jun 21 '22 at 09:54
what did you expect to happen by calling `setTime` again in `setTime` ? I suppose you want to assign the parameters to the member variables — 463035818_is_not_an_ai, Jun 21 '22 at 09:56
you seem to be under the impression that there is a lot of magic going on (a declaration being sufficient, a setter automagically setting members), but its much more boring than that, your code only does what you told it to do. If you want a constructor to do something you need to define what that something is, if you want a setter to set members you need to write the code for that — 463035818_is_not_an_ai, Jun 21 '22 at 09:59
This is how `setTime` should look `void Time::setTime(int hour, int minute, int second) { this->hour = hour; this->minute = minute; this->second = second; }` — john, Jun 21 '22 at 10:03
1) There is an extra `{` near "Time::printStandard()". I don't think it will compile. 2) The line `hour-1200;` doesn't do anything (the intent may be to change the variable by subtracting a value from the existing value). — Peter Mortensen, Jul 08 '22 at 10:07
Why are the file names capitalised (TIME.H)? A remnant [from Turbo C++](https://www.quora.com/What-are-some-bitter-truths-about-engineering-in-India/answer/Adhokshaj-Mishra)? What operating system is this on? — Peter Mortensen, Jul 08 '22 at 10:19

Jason · Accepted Answer · 2022-06-21T10:06:44.523

3

The problem is that you've not implemented the constructor Time::Time(int, int, int) in your source file.

To solve this just add a definition for Time::Time(int, int, int).

TIME.CPP

//implmentation for constructor that was not there before
Time::Time(int phour, int pminute, int psecond): hour(phour), minute(pminute), second(psecond)
{
    
}
//other code

Working demo

edited Jun 21 '22 at 10:06

answered Jun 21 '22 at 09:38

Jason

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1

It is not the only cause of the error messages though. Probably `TIME.CPP` isn't being compiled at all either. – user17732522 Jun 21 '22 at 09:44
1

*One* of the problems... – Paul Sanders Jun 21 '22 at 09:57
@PaulSanders No, read the title again. It says *"Undefined Reference to Time::Time(int,int,int)"* and in the given example there is no definition for `Time::Time(int, int, int)` but there is definition for other members. So it is natural to answer accordingly. Ofcourse there may be other problem but i answer according to the question being asked. – Jason Jun 21 '22 at 10:01
1

@user17732522 Maybe. But the title asks specifically asks about the constructor and there is missing definition for the constructor. So i answered accordingly. Ofcourse there may be other problem with the code which i haven't covered as i want to address only the question being asked. – Jason Jun 21 '22 at 10:03
1

_I want to address only the question being asked_ That is not a philosopy I agree with. And if you read the body of the question, there are two linker errors (with two different underlying causes), not one. – Paul Sanders Jun 21 '22 at 10:51
@PaulSanders That's my point.I answered according to my understanding(and philosophy) of the question. This is what i did(or always always always do) in steps. 1) I went to onlinegdb.com 2) then i just copy/paste the code from OP's question to the online compiler 3) Then i fix the errors there 4) I report back the errors that i fixed there& 5) Finally i paste the link to the online compiler. This is all i do when i see an MRE. There's nothing wrong in doing that. And IMO it is the best and fastest way to solve a problem.Ofcourse there can be other logical errors but i am not addressing them. – Jason Jun 21 '22 at 11:03
@PaulSanders As i said, ofcourse there can be other logical errors in the program but when i have a MRE available and a specific error(also stated in the question by OP) from that MRE then i just answer that particular question. – Jason Jun 21 '22 at 11:05

Undefined Reference to Time::Time(int,int,int)

TIME.H

TIME.CPP

MAIN.CPP

1 Answers1