program help

[mike3x1]

Hi
i'm having a few problems..i'm trying to do a time class
that holds the hr, min , and meridian( am or Pm).
this is what i have so far. For the void set how would i set the char mer[] to am or pm.
class Time
{
long hr, min;
char meridian[5];

public:

void Set(long h, long m, char mer[]);
void Set(char string_time[]);

}

[gusano79]

...
For the void set how would i set the char mer[] to am or pm.
...

The sprintf function should work for that:

#include <stdio.h>

void Set(char string_time[])
{
    sprintf(meridian, string_time);
}

If you do this with string_time larger than meridian, it will crash and burn horribly.

I recommend that you don't store and manipulate that value as a char array. If it's only going to ever have two distinct values, it's a lot easier to handle if you use a simpler type, like an int, for example. Just decide on a meaning for the simpler variable, e.g. a zero int value means "AM" and nonzero means "PM". If you're writing C++, then a bool is even better--it only has two possible values. The only time you need text is when you're displaying the time for a human being, which can be done in a separate function that interprets the numeric values and prints out the textual meaning. This will make your code simpler and easier to work with.

[Fili]

There is a time structure you know-- see gettime() : :lol:

[gusano79]

There certainly is... Using the library functions as much as possible is good (code reuse, more sleep)--but it can be quite educational to write your own as well. It builds character, puts hair on your eyeballs, that sort of thing.

[Chainsaw]

It depends on what you want to DO with this class, of course, but if it were me I'd either make meridian stored as a bool or just store the time as 24 hour time.

Say your class was like this:

class ATimeOfDay
{
int hours, minutes;
bool AM;

public:

// meridian had better be "am" or "pm" or "AM" or "PM" or the like!
// hours can be 0..12, minutes 0..59.
// anything else returns false.
bool SetTime( int hours, int minutes, const char* meridian );

// here hours can be 0..23 and minutes 0..59.
// hours >= 12 implies 'pm'
bool Set24HourTime( int hours, int minutes );

// initialize in constructor
ATimeOfDay();
};

So, the advantage of a bool for AM means you don't have to constantly test against some string. You can say:

if (AM) printf("It is the morning\n");

rather than

if (strcmp(meridian,"am")==0) printf("It is the morning\n");

Just a suggestion!

[K-1]

Hi
i'm having a few problems..i'm trying to do a time class
that holds the hr, min , and meridian( am or Pm).
this is what i have so far. For the void set how would i set the char mer[] to am or pm.

class time 
{
private:
    int hour, minute;
public:
   void set(int h, int m, bool am);
   void display();
};

void time::set(int h, int m, bool am)
{
    minute = m;
    if am
       hour=h;
    else
       hour=h+12;
}
void time::display()
{
    if(hour<13)
        cout<<hour<<":"<<minute<<" am"<<endl;  //or whatver output function you use
    else
        cout<<hour-12<<":"<<minutes<<" pm"<<endl;
}