Problem with time program

Hi, I have a program which is supposed to give the time elapsed from a given time to another given time. There were three functions which were incomplete setTime(), display1Time()and elapsed(). I have created a solution for two of the functions, but found that there are some erros which I do not understand and was wondering if I can get your help to correct these errors and make the program work completely.My code is displayed below:

Code:

// Incomplete version
// Starting code for student tutorial

#include <iostream>
using namespace std;

struct Mytime
{
   int hours;
   int mins;
};

int timecmp( Mytime, Mytime );
// compares two Mytime values
// returns 0 if times are same
// returns >0 if first is later than second
// returns <0 if first is before second

int setTime( Mytime& t, int h, int m );
// if valid time sets hh and mm to h and m 
// and returns 0
// if invalid returns integer > 0 as error code
// error code +1 = underflow hours
// error code +2 = overflow hours
// error code +4 = underflow mins
// error code +8 = overflow mins

void display1Time( Mytime t );
// displays in form hh:mm

void elapsed( Mytime t1, Mytime t2, Mytime& duration );
// determines the time duration between t1 and t2
// t1 assumed to be earlier than t2

int main()
{
    Mytime now;
    Mytime then;
    Mytime howlong;
    
    int h,m;
    
    do // validate input
    {
        cout << "Enter start hh mm : ";
        cin >> h >> m ;
    } while (setTime(now,h,m));
    
    do
    {
        cout << "Enter finish hh mm : ";
        cin >> h >> m ;
    } while (setTime(then,h,m));
    
    elapsed(now,then,howlong);

    cout << "Time elapsed from ";
    display1Time(now);
    cout << " until ";
    display1Time(then);
    
    cout << " is ";
    display1Time(howlong);
    cout << endl;
    return ( 0 );
}


int timecmp(Mytime t1,Mytime t2)
{
   if (t1.hours == t2.hours)
   {
      if (t1.mins == t2.mins)
      {
         return 0;
      }
      else // mins not same
      {
         if (t1.mins > t2.mins)
         {
            return 1; // greater than zero
         }
         else
         {
            return -1;
         }
      }
   }
   else // hours not same
   {
      if (t1.hours > t2.hours)
      {
         return 1;
      }
      else
      {
         return -1;
      }
   }
}


int setTime(Mytime& t, int h, int m )
{
   
  if (h < 0)
   {
      return 1; // error code +1 = underflow hours
   }
  else if (h > 23)
   {
      return 2; // error code +2 = overflow hours
   }
  if (m < 0)
   {
      return 4; // error code +4 = underflow mins
   }
  else if (m > 60)
   {
      return 8; // error code +8 = overflow mins
   }
 
    t.hours = h;
    t.mins = m;
    return 0;
}

void display1Time(Mytime t)
{
  if (h > 10) 
   {
      cout << h << endl;
   }
  else
   {
      cout << "0" << h << endl;
   }
  if (m > 10)
   {
      cout << m << endl;
   }
  else
   {
      cout << "0" << m << endl;
   }

  cout << h << ":" << m << endl;
}


void elapsed(Mytime t1, Mytime t2, Mytime& duration)
{
    setTime(duration,0,0);
}

I have completed the functions for setTime() and display1Time(), but these have caused the following errors:

Code:

time.cc: In function `void display1Time(Mytime)':
time.cc:133: `h' undeclared (first use this function)
time.cc:133: (Each undeclared identifier is reported only once
time.cc:133: for each function it appears in.)
time.cc:141: `m' undeclared (first use this function)

I tried correcting this error by changing the function to void display1Time (int h, int m) but this did not work saying the following:

Code:

16 jaguar% g++ time.cc
time.cc: In function `int main()':
time.cc:58: `struct Mytime' used where a `int' was expected
time.cc:60: `struct Mytime' used where a `int' was expected
time.cc:63: `struct Mytime' used where a `int' was expected

Hope you can help me. Also, I would like to know how to approach the function elapsed().

Thank you if you can help.

So you don't want to use random data inside your displaytime function; you want to display the data inside the object. You use dots to access the fields of an object (see your set function for an example).

There appeas to be no erros now when I compile it, but my output displays the following:

Code:

9 jaguar% g++ time.cc
10 jaguar% ./a.out
Enter start hh mm : 7 30
Enter finish hh mm : 7 29
Time elapsed from 07
30
7:30
 until 07
29
7:29
 is 00
00
0:0

Well, that's how you told it to print: The hours, a new line, the minutes, a new line, and then the time with a colon.

And currently your elapsed always returns 0:0 so that's expected too.

So I just need to take out the new lines and it should display as normal? Also I have not completed the elapsed() function yet, so I will expect the output to be 0:0