These are exact copies of examples from my textbook.
when I tried to compile them
I got this message:
[Linker error] undefined reference to `WinMain@16'
ld returned 1 exit status
I tired to research on the internet,
some people recommended adding "int main()" to the implementation file, which did not work.
Please help me...
---------------------------dtime.cpp---------------------------
Code:
#include
#include
#include
#include "dtime.h"
using namespace std;
void read_hour(istream& ins, int& the_hour);
void read_minute(istream& ins, int& the_minute);
int digit_to_int(char c);
bool operator ==(const DigitalTime& time1, const DigitalTime& time2)
{
return (time1.hour == time2.hour && time1.minute == time2.minute);
}
DigitalTime::DigitalTime(int the_hour, int the_minute)
{
if (the_hour < 0 || the_hour > 23 || the_minute < 0 || the_minute > 59)
{
cout << "Illegal argument to DigitalTime constructor.";
exit(1);
}
else
{
hour = the_hour;
minute = the_minute;
}
}
DigitalTime::DigitalTime( ) : hour(0), minute(0)
{
//Body intentionally empty.
}
void DigitalTime::advance(int minutes_added)
{
int gross_minutes = minute + minutes_added;
minute = gross_minutes%60;
int hour_adjustment = gross_minutes/60;
hour = (hour + hour_adjustment)%24;
}
void DigitalTime::advance(int hours_added, int minutes_added)
{
hour = (hour + hours_added)%24;
advance(minutes_added);
}
//Uses iostream:
ostream& operator <<(ostream& outs, const DigitalTime& the_object)
{
outs << the_object.hour << ':';
if (the_object.minute < 10)
outs << '0';
outs << the_object.minute;
return outs;
}
//Uses iostream:
istream& operator >>(istream& ins, DigitalTime& the_object)
{
read_hour(ins, the_object.hour);
read_minute(ins, the_object.minute);
return ins;
}
int digit_to_int(char c)
{
return ( int(c) - int('0') );
}
//Uses iostream, cctype, and cstdlib:
void read_minute(istream& ins, int& the_minute)
{
char c1, c2;
ins >> c1 >> c2;
if (!(isdigit(c1) && isdigit(c2)))
{
cout << "Error illegal input to read_minute\n";
exit(1);
}
the_minute = digit_to_int(c1)*10 + digit_to_int(c2);
if (the_minute < 0 || the_minute > 59)
{
cout << "Error illegal input to read_minute\n";
exit(1);
}
}
//Uses iostream, cctype, and cstdlib:
void read_hour(istream& ins, int& the_hour)
{
char c1, c2;
ins >> c1 >> c2;
if ( !( isdigit(c1) && (isdigit(c2) || c2 == ':' ) ) )
{
cout << "Error illegal input to read_hour\n";
exit(1);
}
if (isdigit(c1) && c2 == ':')
{
the_hour = digit_to_int(c1);
}
else //(isdigit(c1) && isdigit(c2))
{
the_hour = digit_to_int(c1)*10 + digit_to_int(c2);
ins >> c2;//discard ':'
if (c2 != ':')
{
cout << "Error illegal input to read_hour\n";
exit(1);
}
}
if ( the_hour < 0 || the_hour > 23 )
{
cout << "Error illegal input to read_hour\n";
exit(1);
}
}
------------------------------dtime.h------------------------------
Code:
#include
using namespace std;
class DigitalTime
{
public:
friend bool operator ==(const DigitalTime& time1, const DigitalTime& time2);
DigitalTime(int the_hour, int the_minute);
DigitalTime( );
void advance(int minutes_added);
void advance(int hours_added, int minutes_added);
friend istream& operator >>(istream& ins, DigitalTime& the_object);
friend ostream& operator <<(ostream& outs, const DigitalTime& the_object);
private:
int hour;
int minute;
};
---------------------------timedemo.cpp:---------------------------
Code:
#include
#include "dtime.h"
using namespace std;
int main( )
{
DigitalTime clock, old_clock;
cout << "Enter the time in 24 hour notation: ";
cin >> clock;
old_clock = clock;
clock.advance(15);
if (clock == old_clock)
cout << "Something is wrong.";
cout << "You entered " << old_clock << endl;
cout << "15 minutes later the time will be "
<< clock << endl;
clock.advance(2, 15);
cout << "2 hours and 15 minutes after that\n"
<< "the time will be "
<< clock << endl;
return 0;
}
O well, thanks for the help.
Linear Mode
