Hi ,
i think this is the same problem a fellow class member has written about. But ,this program calculates the time elapsed between two clock times entered at the command line. I have completed it however there is something wrong with my error checking function setTime()
at present when entering" start time: 7 30 ,Finish time: 7 29 "the elapsed time is suppose to be 23:59 however mine is 0 : -1. Specifying 1 minute instead of 23 hours and 59 minutes. If i put in other time such as 7 30 to 23 30 it does calculate the time correctly at 16: 0 hours.
Oh and it is meant to return an Error code if the time entered is in an incorrect format-which i cannot get it to do either, any ideas?

include <iostream>
using namespace std;

struct Mytime
{
int hours;
int mins;
};

int timecmp( Mytime, Mytime );

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 );


void elapsed( Mytime t1, Mytime t2, Mytime& duration );

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 )
{
t.hours = h;
t.mins = m;

if (t.hours >= 0 && t.hours <= 23)
{
if (t.mins >= 0 && t.mins <= 60 )
{
return 0;
}
}
else // Data invalid
{

if (t.hours < 0)
{
cerr << "+1" << endl; // Error code returned
}

else if (t.hours > 23 )
{
cerr << "+2" << endl;
else if( t.mins < 0)

{
cerr << "+4" << endl;
}

if (t.mins > 60 )
{
cerr << "+8" << endl;
}
else
{
return 0;
}

}
}

void display1Time(Mytime t)
{
cout << t.hours << ":" << t.mins; //Displays calculated time
}


void elapsed(Mytime t1, Mytime t2, Mytime& duration)
{
duration.hours = t2.hours - t1.hours;
duration.mins = t2.mins -t1.mins;// Time elapsed calculated

}
i have adapted the code to include the error checking, it is working however not correctly

This post has been edited by Tara200: 27 Jan, 2008 - 02:38 PM

You could add some condition that if the start time is after the finish time, add 24 hours.

Any ideas how to do that GWatt? I tried to add a control for the time setting it to 24 hr clock as it is suppose to be but that didn't work either?

i think you missed out a } in the int setTime function