C / C++ / MFC

24-Mar-09 0:59

Hi people,

I dont know if anyone can help really, I have got to set up an array of size 20 easy Smile | :)

but what i need to do and not sure how to is to randomly assign 6 positions in the array with a 1. Any ideas?

Mahesh Kulkarni24-Mar-09 1:24

Mahesh Kulkarni

24-Mar-09 1:24

if u want to fill six positions out of 20 you can use
Array[rand()%20] = somevalue..

are you looking for this functionality?

The secret of life is not enjoyment
but education through experience.
- Swami Vivekananda.

Neal beavis24-Mar-09 1:27

24-Mar-09 1:27

thank you very much do u do thi whilst you are declaring it? or in the main part of code?

Eytukan24-Mar-09 1:27

24-Mar-09 1:27

You need to generate

int arr[20]={0};
for(int i=0;i<6;i++)
{
    int i = 0 + rand() % (19 - 0);
    arr[i]=1;
    printf("\n%d",i);
}
for(int i=0;i<19;i++)
{
    printf("\n%d",arr[i]);
}

You might also add a condition to check for repetitions in the random generated nos.

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Neal beavis24-Mar-09 1:30

24-Mar-09 1:30

printf("\n%d", what exactly does that do?

CPallini24-Mar-09 1:34

24-Mar-09 1:34

C tutorial needed. Anyway see [^].
Smile | :)

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Eytukan24-Mar-09 1:36

24-Mar-09 1:36

Too many trivias today Sigh | :sigh:

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

CPallini24-Mar-09 1:33

24-Mar-09 1:33

VuNic wrote:
int i = 0 + rand() % (19 - 0)

You shouldn't overindulge in beer, in the morning... Roll eyes | :rolleyes:

Eytukan24-Mar-09 1:35

24-Mar-09 1:35

Hey I thought of saying a word about it but forgot.
Okay, to the OP:
It specifies the range. If you want to generate between, 10 to 20,
You can change it to

int i = 10 + rand() % (20 - 10)

lol that would look funny without the explanation Big Grin | :-D

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Neal beavis24-Mar-09 1:39

24-Mar-09 1:39

you have lost me i still dont understand wot printf("\n%d", is used for?

Eytukan24-Mar-09 1:43

24-Mar-09 1:43

Pardon me, I would want to rewrite my reply.

    int arr[20]={0};
for(int i=0;i<6;i++)
{
    int i = 0 + rand() % (19 - 0);
    arr[i]=1;

}
for(int i=0;i<19;i++)
{

}

Explanation Here[^]

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

David Crow24-Mar-09 2:41

David Crow

24-Mar-09 2:41

Neal beavis wrote:
...i still dont understand wot printf("\n%d", is used for?

Did you consult the MSDN page that was mentioned? It says right there in black & white what printf() does.

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CPallini24-Mar-09 1:43

24-Mar-09 1:43

Anyway there's a flaw, it should be:

int i = 10 + rand() % (21 - 10);

to generate a number ranging from 10 to 20 (including bounds).
In the above example you may also be correct (because you didn't mentionate of including both of the bounds), but in your original post, (19-0) is wrong, because rand() % (19-0) ranges from 0 to 18 (bounds included).
-- Carlo the Nitpick.

Smile | :)

Eytukan24-Mar-09 1:53

24-Mar-09 1:53

Silent. Let him use it. This is not a bug. Because it won't crash his program nor he will ever come to know it. It looses both the qualification of being a bug. So Jig | [Dance]

it cannot be booked. $Shucks | :-\$ lol, let me change it Smile | :)

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

CPallini24-Mar-09 3:22

Re: ODBC database problem

24-Mar-09 3:22

ODBC database problem

Deepu Antony24-Mar-09 0:55

Deepu Antony

24-Mar-09 0:55

Hi all

I am using a database application program using ODBC with MS Access as the database.
While navigating through the database,it is missing a particular row.

my code look like this

m_rs.Open( CRecordset::snapshot, _T( "SELECT * FROM DAUArinc717Frame2" ) );
m_rs.Move( Index );
for(i=0;i<128;i++)
{

data = (BYTE)strtoul( m_edit2, 0, 16 );
str.Format("%d",data);

m_rs.Edit();
m_rs.m_Data = str;
m_rs.Update();
m_rs.MoveNext();

b2 = strtoul( m_edit2, 0, 16 )>> 8;
str.Format("%d",b2);
m_rs.Edit();
m_rs.m_Data = str;
m_rs.Update();
m_rs.MoveNext();

}

I am updating to the database, the values read from the GUI.In this process when i==3,in that particular location in my database(row==264),it is skipping without updating and is moving to the next row.

Please help me..

Thanks in advance

Regards
Deepu

David Crow24-Mar-09 2:48

David Crow

24-Mar-09 2:48

Deepu Antony wrote:
In this process when i==3,in that particular location in my database(row==264),it is skipping without updating and is moving to the next row.

So does Update() throw an (CDBException) exception?

Re: ODBC database problem

Deepu Antony24-Mar-09 3:23

Deepu Antony

24-Mar-09 3:23

Thanks for the reply.
it is working now.I didn't changed anything.Sometimes it happens like that.
Don't know the exact reason

error LNK2001: unresolved external symbol

ytubis24-Mar-09 0:26

ytubis

24-Mar-09 0:26

Hi!
I need help with this problem, I got this error before but I managed to solve.
But now I have a case with the virtual function.
The source looks like this(after the code I continued writing):

#include "stdafx.h"
#ifndef EMPTRANSH
#define EMPTRANSH
#include "Global.h"
#include "iostream"
#include "string"
using namespace std;

class EmpTrans
{
private:
int id;
char emp_name[MAXNAMELENGTH];
employee_status emp_st;
int salary;
salary_type sal_st;
char deal_date[DATELENGTH];
public:
EmpTrans();
static void Open();
static void Close();
void ReadNext();
virtual void Apply();

void UpdateId(int i){id = i;}
void UpdateSalary(int s){salary = s;}
void UpdateEmployeeStatus(employee_status es){emp_st = es;}
void UpdateSalaryType(salary_type ss){sal_st = ss;}
void UpdateDate(char * d){strcpy(deal_date,d);}
void UpdateEmployeeName(char en){emp_name[0] = en;}
int GetId(){return id;}
char * GetEmployeeName(){return emp_name;}
employee_status GetEmployeeStatus(){return emp_st;}
int GetSalary(){return salary;}
salary_type GetSalaryType(){return sal_st;}
char * GetDate(){return deal_date;}
};
#endif

class EmpTransAdd : public EmpTrans
{
public:
void Apply();
};

class EmpTransChange : public EmpTrans
{
public:
void Apply();
};

class EmpTransDelete : public EmpTrans
{
public:
void Apply();
};

When I compile and link this source I get the error,
when I remove the virtaul function from the Apply function, everything works fine.
What is the problem?
Do I need to take out the other classes from the source? or to include them inside the ifdef?

Thanks Smile | :)

Re: error LNK2001: unresolved external symbol

Cedric Moonen24-Mar-09 0:35

Cedric Moonen

24-Mar-09 0:35

You don't provide a body for the EmpTrans::Open(), EmpTrans::Close(), EmpTrans::Apply functions (well at least you didn't show us). You still need to provide a body for those functions in the base class, unless they are pure virtual functions (e.g. virtual void Apply() = 0;), in which case it is mandatory that each child classes implement this function.

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Re: error LNK2001: unresolved external symbol [modified]

S p k 52124-Mar-09 0:37

S p k 521

24-Mar-09 0:37

Will u pls show the code which creates the instance of ur class EmpTrans?
you have to provide the definition of Apply() in the base class. else it have to be a pure virtual function.

modified on Tuesday, March 24, 2009 6:44 AM

Re: error LNK2001: unresolved external symbol

Eytukan24-Mar-09 0:40