atof only returns integers?

Question

I've got a routine which gets numbers in the exponent format(e.g. 2,5E-02 or 4E+06) as a QString. When I print the values I always only get integers and when they are smaller then 1 I always get 0. Does anyone know what I am doing wrong here? (with the cout line I only wanted to test whether the QString::number() is ruining it for me)

here is a code snippet:

QStringList valPair;
value = atof(valPair[0].replace(",",".").toAscii());
value1 =atof(valPair[1].replace(",",".").toAscii());
strValue = "[" + QString::number(value) + ", " + QString::number(value1) + "]";
//cout<<value<<" "<<value1;

I'd appreciate any help!

EDIT: It was a Problem with variable declaration...

double value, value1;

When you get `2,5E-02` do you print `2` or `0`? If you print `2` then make sure you locale is `C` (`.` is probably not the decimal point in your locale.) http://stackoverflow.com/questions/1333451/c-locale-independent-atof — vladr, Nov 13 '12 at 06:56
@AndreyT now I feel stupid. I declared the values as double and it works. Sorry to bother you all! — samoncode, Nov 13 '12 at 07:07
If you set the locale correctly. Put `std::cout.imbue(std::locale(""));` as the first line in main. Then `operator>>` will decode comma separated numbers (if that is what you expect in your locale as set in your computers settings), — Martin York, Nov 13 '12 at 07:25

score 1 · Answer 1 · answered Nov 13 '12 at 06:57

1

The conversion function doesn't support your locale, which uses comma as a decimal separator. Use 2.4e4 instead.

answered Nov 13 '12 at 06:57

Aki Suihkonen

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Thank you for your effort! But like I wrote in the comment it was just me being stupid. I had to declare the value/value1 variable as double. The problem with the decimal-character I solved with the replace-function. – samoncode Nov 13 '12 at 07:16

score 1 · Accepted Answer · answered Nov 13 '12 at 19:47

Why are you doing all that work? Qt already has what you're looking for if you use QString::toDouble and QString::number(). If you set your locale manually before calling toDouble() then you can use the comma decimal notation without replacing anything.

You could also create a string template like QString("[%1,%2]") and then use the double version of QString::arg.

atof only returns integers?

2 Answers2