C / C++ / MFC

Help with _tioa and other conversion routines

2-Jul-08 17:51

Try this.

int i = 15;
CString str;
str.Format("%03d", i);

-Saurabh

Larry Mills Sr2-Jul-08 12:51

2-Jul-08 12:51

I've tried the conversion routines and still get errors. I receive from an edit box a number. I want to add something to that number and then put it into a CString. can someone show me a code example that works Please. I can get the number find but I can't add something to it and then put it back into a CString.

A C++ programming language novice, but striving to learn

Saurabh.Garg2-Jul-08 16:45

2-Jul-08 16:45

I am sorry, what exactly is the problem? Perhaps some code you tried will help.

-Saurabh

Larry Mills Sr2-Jul-08 17:26

2-Jul-08 17:26

For instance : int a = 42; CString str; int tmp;(pEdit already established) pEdit1->GetDlgItemText(str); now str holds the value the User typed which was NOT a number. but the representation of a number in character format. Now tmp = _tstoi(str); WORKS it changes the character to a number and puts it in tmp(an integer). but my question is How do I do the reverse? How to I get an integer valve into the CString(ie str)?

I've tried these functions: _itot_s, _itoa_s, and _itoa and they all give a long error message basically saying the str cannot be transfered to a char*

I know there is something that works, but I can't recall what it is.

I just want to put an integer value into a CString after I have converted one from the User's entry.

A C++ programming language novice, but striving to learn

Saurabh.Garg2-Jul-08 17:39

2-Jul-08 17:39

Okay I think the problem is _itot excepts second argument to be either wchar_t* or char* depending whether unicode is defined or not and it cannot automatically convert from CString to char* or wchar_t*. I don't use much MFC so not sure if there are function in CString to automatically do this but you can try something like this:

int i = 42;

CString str("50");
int temp = _ttoi(str);
	
temp += i;
TCHAR buffer[50];
_itot(temp, buffer, 10);
str = buffer;

-Saurabh

Larry Mills Sr3-Jul-08 3:55

3-Jul-08 3:55

works until the last statement: str = buffer; at this point buffer does indead have the value I want, but I get an Access violation error when the assignment operator in CString tries to assign buffer's value to the CString(ie str).

A C++ programming language novice, but striving to learn

beko2-Jul-08 19:55

beko

2-Jul-08 19:55

check CString format function

CString tmp;
int a = 5;
tmp.Format("%d Hey ", a);

Hope this helps.

Larry Mills Sr3-Jul-08 4:10

3-Jul-08 4:10

I get this error: "Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast"

A C++ programming language novice, but striving to learn

Mark Salsbery3-Jul-08 7:04

Mark Salsbery

3-Jul-08 7:04

That should be:

CString tmp;
int a = 5;
tmp.Format(_T("%d Hey "), a);

Here's a tip:
Choose a string character type and stick with it.
The three common choices are
char (ANSI)
wchar_t (Unicode)
TCHAR (Generic - either char or wchar_t based on build configuration)

MFC uses generic types and, except for OLD APIs, so does Windows, so if you're using MFC,
generic is probably the best choice - unless you want to have to conver strings every
time you call a Windows or MFC API.

CString is also a generic type - it's either a CStringA (ANSI/char) or
CStringW (Unicode/wchar_t) depending on the build configuration.

If you choose to use the generic types, use them everywhere.
That means:
Use the Generic Text Mappings[^]
Wrap your string literals with the _T() macro
Use CSring instead of CStringA or CStringW

IMO, this stuff should be second-nature. You shouldn't have to think about it.
It's VERY worthwhile to take the time to understand it completely.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Larry Mills Sr3-Jul-08 9:04

'strptime': identifier not found, even with argument-dependent lookup

3-Jul-08 9:04

Thanks Mark

A C++ programming language novice, but striving to learn

dinesh_shads2-Jul-08 12:02

dinesh_shads

2-Jul-08 12:02

Hi,
I have the following issue:

#include <time.h>

....

struct tm tm;
if(strptime("2001-05-21", "%Y-%m-%d", &tm) == NULL)
{
//Some error processing
}

But I seem to be getting the following error when I compile, Can someone please tell me what I am doing wrong?

error C3861: 'strptime': identifier not found, even with argument-dependent lookup

Re: 'strptime': identifier not found, even with argument-dependent lookup

dinesh_shads2-Jul-08 12:04

dinesh_shads

2-Jul-08 12:04

correction
#include < time.h >

Re: 'strptime': identifier not found, even with argument-dependent lookup

Saurabh.Garg2-Jul-08 16:50