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I have created a simple sitch(), it takes integers
int choice;
switch(choice)
case 1:
break
.
.
default
message
break;
this works fine as long as the user enters a number (integers) but if I enter leters a,b,XD ..etc
it goes out in a loop.
how to chakec data type to ensure it is 1-9, if not display a message
Any way would be good
thanx
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Do this before your switch statement:
It just checks if the values are in the specified range.
if (choice >= 48 && choice <= 57)
{
switch (choice)
...
}
this is this.
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Anonymous wrote:
how to chakec data type to ensure it is 1-9, if not display a message
Your switch does this automatically with the default block. What else do you want?
Behind every great black man...
... is the police. - Conspiracy brother
Blog[^]
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Don't think you read the question right. The default works fine if an interger is entered (any number) but if a character is enter, it won't work!!!!!
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Anonymous wrote:
ForumVisual C++
Subject:Re: switch() function
Sender:Anonymous
Date:14:18 7 Jul '05
Don't think you read the question right. The default works fine if an interger is entered (any number) but if a character is enter, it won't work!!!!!
I don't think that you can program very well. That's OK since we are here to help.
I read the question and I can assure you that I understand it perfectly well! Your problem is that you don't know what you are doing. Let me elaborate: characters (I'll stick to single byte characters for simplicity) are represented by integral values in the range 0x0 to 0xFF. Integers (the usual 32bit integers) have values in the range 0x0 to 0xFFFFFFFF. What did we learn from this is that you can store an character into an int without problems. So a simple static_cast will solve your problem.
If you work with the datatype char however, the following code will do the trick:
std::cin >> cYourChar;
switch( cYourChar )
{
case '0': { break; }
case '1': { break; }
case '2': { break; }
case '3': { break; }
case '4': { break; }
case '5': { break; }
case '6': { break; }
case '7': { break; }
case '8': { break; }
case '9': { break; }
default:
}
Behind every great black man...
... is the police. - Conspiracy brother
Blog[^]
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as above, the exception will be caught in the "default" case.
it's not necessarilly the fault of the switch but of the input.
Maximilien Lincourt
Your Head A Splode - Strong Bad
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hi all
I want to use mfc in win32 dll. but this error happens.how to deal with this error?
fatal error C1189: #error :WINDOWS.H already included. MFC apps must not #include <windows.h>
I love you not for whom you are, but who i am when I'm by your side
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gohappy_1999 wrote:
I want to use mfc in win32 dll.
Thats not possible, as MFC is Upgrade/wrapper of Win32 api's. So according to Windows Programming Thumb Rule, Any upgraded thing will not be supported in condition prior to upgrade.
So,In order to use MFC in dll,You have to create MFC based DLL. 
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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I have done some work recently in C#, integrating the product I work on with another project that exposes a COM object for this purpose. Now a third party has asked me to do the same in C++. This product in C# took an array of objects as a parameter, and returned an array of objects. The objects were strings. In C++, I've done this:
const char * pClientFields[11] = {"CLIENT_RECD",<br />
"CLIENT_FIRST",<br />
"CLIENT_LAST",<br />
"CLIENT_ADDRESS",<br />
"CLIENT_CITY",<br />
"CLIENT_STATE",<br />
"CLIENT_ZIP",<br />
"CLIENT_AREA",<br />
"CLIENT_PHONE",<br />
"CLIENT_BUSINESS",<br />
"CLIENT_EMAIL"};<br />
<br />
_variant_t * ClientFields = NULL;<br />
<br />
_variant_t * GetClientFields()<br />
{<br />
if (ClientFields == NULL)<br />
{<br />
CComSafeArray<BSTR> array;<br />
for(int i=0; i < 11; ++i)<br />
{<br />
array.Add(_bstr_t(pClientFields[i]));<br />
}<br />
<br />
VARIANT * pVar = new VARIANT();<br />
pVar->vt = VT_ARRAY | VT_BSTR;<br />
pVar->parray = array.Detach();<br />
<br />
ClientFields = new _variant_t(pVar);<br />
}<br />
<br />
return ClientFields;<br />
}
because the COM interface is expecting a _variant_t( and it returns one, too ). ClientFields at the end of this does not know what sort of variant it is, and so I get an exception. Can anyone please show me what I need to do here to get a _variant_t full of strings, and also how to read one at the other end ? I need it to compile in VC6 ( although the above is written in VC7 )
Christian Graus - Microsoft MVP - C++
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Christian Graus wrote:
Can anyone please show me what I need to do here to get a _variant_t full of strings, and also how to read one at the other end ?
You can create the variant with something like this:
void BstrArrayFromWcharArray(VARIANT& var, WCHAR** pStrings, int size)
{
var.vt = VT_ARRAY | VT_BSTR;
var.parray = SafeArrayCreateVector(VT_BSTR, 0, size);
for (long ix = 0; ix < size; ix++)
SafeArrayPutElement( var.parray, &ix, ::SysAllocString(pStrings[ix]) );
}
WCHAR* pClientFields[] =
{
L"CLIENT_RECD",
L"CLIENT_FIRST",
L"CLIENT_LAST",
L"CLIENT_ADDRESS",
L"CLIENT_CITY",
L"CLIENT_STATE",
L"CLIENT_ZIP",
L"CLIENT_AREA",
L"CLIENT_PHONE",
L"CLIENT_BUSINESS",
L"CLIENT_EMAIL"
};
_variant_t ClientFields;
_variant_t* GetClientFields()
{
if (ClientFields.vt == VT_EMPTY)
{
UINT size = sizeof(pClientFields)/sizeof(*pClientFields);
BstrArrayFromWcharArray(ClientFields, pClientFields, size);
}
return &ClientFields;
}
You can access the elements of the array inside the variant with something like this:
void ShowBstrArray(const VARIANT var)
{
if (var.vt != (VT_ARRAY | VT_BSTR))
return;
SAFEARRAY* psa = var.parray;
for (long i = 0; i < (long)psa->rgsabound[0].cElements; i++)
{
BSTR bstr;
SafeArrayGetElement(psa, &i, &bstr);
CString s = bstr;
AfxMessageBox(s);
}
}
void Test()
{
_variant_t* pFields = GetClientFields();
ShowBstrArray(*pFields);
}
However, when accessing most or all of the elements in the array, the following alternatives, which make use of SafeArrayAccessData, are more efficient:
void BstrArrayFromWcharArray2(VARIANT& var, WCHAR** pStrings, UINT size)
{
var.vt = VT_ARRAY | VT_BSTR;
var.parray = SafeArrayCreateVector(VT_BSTR, 0, size);
BSTR HUGEP* pbstr = NULL;
if (FAILED(SafeArrayAccessData(var.parray, (void HUGEP**)&pbstr)))
return;
for (UINT ix = 0; ix < size; ix++)
pbstr[ix] = ::SysAllocString(pStrings[ix]);
SafeArrayUnaccessData(var.parray);
}
void ShowBstrArray2(const VARIANT var)
{
if (var.vt != (VT_ARRAY | VT_BSTR))
return;
SAFEARRAY* psa = var.parray;
BSTR HUGEP* pbstr = NULL;
if (FAILED(SafeArrayAccessData(psa, (void HUGEP**)&pbstr)))
return;
for (UINT i = 0; i < psa->rgsabound[0].cElements; i++)
{
CString s = pbstr[i];
AfxMessageBox(s);
}
SafeArrayUnaccessData(psa);
}
I tried it with VS6 and it seemed to work fine. Hope that helps,
--
jlr
http://jlamas.blogspot.com/[^]
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Wow - that's a lot of code, thanks for going to this effort for me.
Christian Graus - Microsoft MVP - C++
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I create a table A in the Oracle.
CREATE TABLE A
(
ID NUMBER(7) primary key
);
Now ,I want to insert a reocrd in the table A;
_ConnectionPtr pConn=NULL;
pConn.CreateInstance(__uuidof(Connection));
_RecordsetPtr pRst=NULL;
pRst.CreateInstance(__uuidof(Recordset));
pConn->Provider="OraOLEDB.Oracle.1";
try
{
pConn->Open("","ISVISION","ISVISION",NULL);
pRst->CursorLocation=adUseClient;
pRst->Open("A",pConn.GetInterfacePtr(),adOpenStatic,adLockOptimistic,adCmdTable);
pRst->AddNew();
pRst->Fields->Item[0L]->Value=100L; //But it throw a excpetion here. I dont know the reason. If I alter the datatype of ID to CHAR(10),it is all right.
//这里就会出现异常，如果表A的ID的数据类型是CHAR(10)的，又不会出错？
pRst->Update();
pRst->Close();
pConn->Close();
}
catch (_com_error& e)
{
MessageBox(e.Description(),"error",MB_OK|MB_ICONWARNING);
return ;
}
if (pConn)
pConn.Release();
if (pRst)
pRst.Release();
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I am trying to maintain someone elses code and do not fully understand it's nuances. However I am trying to recover a string stored in a CComboBox list.
I posted this at little earlier at 19:50 but some of the code was missing/corrupted
//---------------------------------
void Control::DoDataExchange(CDataExchange* pDX)
{
Sheet* pSheet = ((C_App*)AfxGetApp())->getSheet();
MyPropertyPage::DoDataExchange(pDX);
//{{AFX_DATA_MAP(Control)
DDX_Control(pDX, IDC_OTHER_COMBO, m_otherCombo); // IDC_OTHER_COMBO is the CComboBox ID:
//}}AFX_DATA_MAP
}
//---------------------------------
//Sheet::PopulateOtherCombo()
{
int i;
int entry=0;
int index=0;
CString name;
for (i=0;i<maxcount;i++)
{
="" some="" code="" that="" constructs="" the="" string="" 'name'
=""
="" write="" 'name'="" to="" ccombobox
index="getControl()-">m_otherCombo.AddString(name);
if (index != CB_ERR)
{
getControl()->m_otherCombo.SetItemData(index, entry++);
}
}
}
//---------------------------------------------------------------------------
//So far I have built a list of strings stored sequentially by 'index' but how do I recover a string ??
// When I click on the CComboBox, the list opens and I can select any of the entries.
int index = getControl()->m_otherCombo.GetCurSel();
// Gets the index # of the currently selected CComboBox entry.
// Now I want to copy the text of the currently selected entry somewhere else.
// I have the index but there is no GetString(index) function
// HELP!
Thanks for any help you can offer
Charles
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The code gets 'corrupted' because you didn't check the box that says 'Do not treat <'s as HTML tags'. Edit this post so we can see the code, then you may get a reply
Christian Graus - Microsoft MVP - C++
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new to the forum. I'll look for it next time. meanwhile Brad Bruce suggested GetLBText. thanks anyway
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Thqanks Brad
works great
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If by 'recover' you mean get the currently selected item in the combobox, I use GetWindowText().
"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown
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sorry some code went missing when I pasted.. here it is again
void Control::DoDataExchange(CDataExchange* pDX)
{
Sheet* pSheet = ((C_App*)AfxGetApp())->getSheet();
MyPropertyPage::DoDataExchange(pDX);
//{{AFX_DATA_MAP(Control)
DDX_Control(pDX, IDC_OTHER_COMBO, m_otherCombo); // IDC_OTHER_COMBO is the CComboBox ID:
//}}AFX_DATA_MAP
}
//-----------------------------------------------------------------
Sheet::PopulateOtherCombo()
{
int i;
int entry=0;
int index=0;
CString name;
for (i=0;i<max_count;i++)
{
=""
="" some="" code="" that="" constructs="" the="" string="" 'name'
=""
="" write="" 'name'="" to="" ccombobox
="" index="getControl()-">m_otherCombo.AddString(name);
if (index != CB_ERR)
{
getControl()->m_otherCombo.SetItemData(index, entry++);
}
}
}
//---------------------------------------------------------------------------
//So far I have built a list of strings stored sequentially by 'index' but how do I recover a string ??
// When I click on the CComboBox, the list opens and I can select one of the entries
int index = getControl()->m_otherCombo.GetCurSel();
// Gets the index # of the currently selected CComboBox entry.
// Now I want to copy the text of the currently selected entry somewhere else.
// I have the index but there is no GetString(index) function
// HELP!
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what function would take
int i = 36;
to a char c?
I'm not an expert yet, but I play one at work. Yeah and here too.
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as suggested, char c = (char)i; is correct but can cause a warning as you could lost some data.
char (which mean signed char) can contain values from -128 to +127, so any value of your int that is out of bound would be truncated...
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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toxcct wrote:
as suggested, char c = (char)i; is correct but can cause a warning as you could lost some data.
char (which mean signed char) can contain values from -128 to +127, so any value of your int that is out of bound would be truncated...
Since an int is 4 times the size of a char, the value will always be truncated! One way to make sure that your value has the same sign bit as the previous int variable is:
c = (i & 0x80000000) ? c | 0x80 : c & 0x7F
Here your test the sign bit i & 0x80000000. Depending on it is set, you set or remove the sign bit from the char.
Behind every great black man...
... is the police. - Conspiracy brother
Blog[^]
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when you copy a signed integer (either char, short, int or long), the sign bit is copied too...
so, making this will work without any data loss :
int i = -2;
char c = (char) i;
ASSERT(c == -2);
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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