Beginner's troubles

[Gregor Pavlic]

Hi, I'm new to this forum and C++... I created this thread to post problems if I have one and I hope you will help me...


Exercise:
Write a class member that holds information about a member of a sports club. Member details include name, surname, year of entry into the club and the ID number(of course this is a simplified example).
Write Display method to display information about member. The main program creates two objects of type member: information about both objects is read by the keyboard. Then you must display data using the Display method...

#include <iostream>

using namespace std;

class Member
{
    private:
        char cName[20];
        char cSurname[20];
        int iEntry_year;
        int iID;
    public:
        Member()
        {
            cout << "Enter name: ";
            cin.getline(cName, 20);
            cout << "Enter surname: ";
            cin.getline(cSurname, 20);
            cout << "Enter entry year: ";
            cin >> iEntry_year;
            cout << "Enter ID number: ";
            cin >> iID;
        }
        void display()
        {
            cout << "Information on member: " << endl;
            cout << cName << endl << cSurname << endl << iEntry_year << endl << iID << endl;
        }
};
int main()
{
    Member member1;
    member1.display();
    Member member2;
    member2.display();
    Member member3;
    member3.display();
    return 0;
};

The big question is, why can I enter cName only on first object??? The second object goes directly to cSurname... Can someone explain to me why??
Can I use constructor this way, or should I make a new function for the input information?
Thanks in advance...

[Texan40]

I would definitely suggest putting the user input in a separate function (perhaps not even on the class itself) and using the input to pass to a constructor or something.

[Peter87]

getline reads until it finds a new line character.
cin >> iID; reads the next integer and leaves the new line character in the stream.
When you next time call getline it will read what was left on the line.

[Gregor Pavlic]

Peter87 how can I fix this...

[Peter87]

One way could be to always use getline and use stringstream to read the numbers out from it. It becomes a little bit more complicated but if you know how stringstream work it's not hard to do.

Another way could be to always call getline until you have read non-empty string.

If you do any of this you probably wan to create functions so you don't have to write the same over and over.

[Texan40]

add this line after your iID input line: cin.ignore(20); cin.clear(); //This will clear the input buffer so getline will work properly on the next iteration.

[Peter87]

Don't do what Texan40 say. It will not work.

[Texan40]

Or you can read for yourself...

http://www.parashift.com/c++-faq-lite/input-output.html#faq-15.6

[Gregor Pavlic]

I added cin.ignore(); behind the last cin >> and now works...
Thank you very much...

[Gregor Pavlic]

Have another problem, this time with RAND...

#include <iostream>
#include <stdlib.h>
#include<time.h>

using namespace std;

int main()
{
    srand(time(NULL));
    int iXposition[8], iYposition[8];
    for(int x = 0;x < 8;x++)
    {
        iXposition[x] = rand() % 39 + 10;
        iYposition[x] = rand() % 19 + 5;
    }
    for(int x = 0;x < 8;x++)
    {
        cout << iXposition[x] << "-" << iYposition[x] << endl;
    }
return 0;
}

iXposition goes over 39 and iYposition goes over 19... I don't know why...
Thanks...

[Peter87]

rand() % 39 gives you a value 0-38 so rand() % 39 + 10 gives you a value 10-48.

[Gregor Pavlic]

So if I want a values between 5 and 39, I must write code:

rand() % 34 + 5;

[Lynx876]

Here's a function I wrote for this, because I always hated trying to remember how to get a ranged random number, lol:

int randomRange( int _Min, int _Max )
{
	//include this library
	//#include <time.h>


	//include this call in the code before hand. ( main() )
	//srand( unsigned ( time (NULL) ) );


	//add 1 to the max, so it's included in the result.
	_Max += 1;

	int x = _Min + ( rand() % ( _Max - _Min ) );

	return x;
}

Then you can simply do the following:

	iXposition[x] = randomRange( 10, 39 );
        iYposition[x] = randomRange( 5, 19 );