how to transfer Cstring to float

camuoi288

How to transfer Cstring type like : 6.591E+02 to float type. exmple : Cstring a="6.591E+02"; float b; and i want b=6.591E+02.I work with MFC.Thanks.

Rajesh R Subramanian

"Real men drive manual transmission" - Rajesh.

camuoi288

I also used atof(),but with atof() parameter in atof()function is char * but my string is Cstring.:(

Rajesh R Subramanian

If you're doing a Unicode build, you could use _ttof() and otherwise atof() will work. For example, this code will work for an MBCS build:

double df = 0;
CString str = "6.591E+02";
df = atof(str);

Hint: CString has the LPCTSTR operator defined, so the conversion will be done automatically.

"Real men drive manual transmission" - Rajesh.

venkatmakam

Let your variable is

CString strFloat;

then use atof as

atof(strFloat.GetBuffer());

Rajesh R Subramanian

That's a misuse of CString::GetBuffer().

"Real men drive manual transmission" - Rajesh.

Cool_Dev

CString a = "6.591E+02";
float b;
sscanf(a,"%E",&b); //use _stscanf() for unicode suppport

CString a = "6.591E+02";
float b;
b = atof(a); // use _ttof() for unicode support

modified on Wednesday, April 20, 2011 6:03 AM

Hans Dietrich

camuoi288 wrote:

atof() parameter in atof()function is char * but my string is Cstring

That is not correct. From MSDN:

double atof(const char \*string);

Since CString has LPCTSTR operator, you can easily call atof like this:

CString str = "1.234";
double d = atof(str);

Best wishes, Hans

Niklas L

Since you're using C++ I suggest using streams.

#include <sstream>
{
CString strFloat("3.5");
istringstream is(strFloat);
float myFloat;
is >> myFloat;
}

This way you can catch errors easily. Consider the following:

float af = atof("a");
float zerof = atof("0");

Both af and zerof will be 0, since on error atof() will return 0. Using streams you can check the stream status after conversion:

{
CString strFloat("3.5");
istringstream is(strFloat);
float myFloat;
is >> myFloat;
if (is.fail())
{
// Conversion failed!
}
}