A problem of setting precison

[ysapex]

I appreciate all the answers from you, thank you very much.

I must stress, the program I wrote is a Win32 program, so I can not use C++, I just want to know if I can find a way to control the float value's precision using C instead of C++:

I recently wrote a programme under Win32 environment, I have a problem which I can not solve independently.

double a ;

TCHAR *k = "152.3", DigitArray[ 100 ] ;

a = strtod( k, NULL ) ; // convert a string to double.

a + = 100 ;

_gvct( a, 100, DigitArray ) ; //Convert double to string.

TextOut( hdc, 0, 0, DigitArray, NULL ) ;

The value of 'a' would be shown as 252.29999999999993, just becaue the default precision is 14 after the decimial point, I hope the value is 252.3 instead of 252.29999999999993, so I wish somebody can tell me a way to solve the above-mentioned problem.

IMPORTANT:

Only C language is acceptable, any methods based on C++ is

not valid !

Thank you very much!

[Richard.J]

I would do a
sscanf( k, "%lf", &a );
a+= 100;
sprintf( DigitArray, "%lf", a);

That should do it (not tested).

[ysapex]

because it includes the operation of FILE read-out and write-in, I think it is not necessary at all.

[HeartBreakKid]

?

_snprintf(DigitArray, 100, "%.01f", a);

[Richard.J]

Originally posted by ysapex
because it includes the operation of FILE read-out and write-in, I think it is not necessary at all.

where do you think is file i/o used?
s[printf|scanf] are buffer related, i. e. memory related.
Go read some books on the basics of C.

[Bond]

Probably just confused sscanf with fscanf.