How to differentiate between an atof of a character vs an input of zero

Asked Jul 25 '17 at 14:01

Active Jul 25 '17 at 14:05

Viewed 38 times

atof() returns 0.0 if it its argument cannot be parsed as a valid float.

How do I differentiate that from when it is given an actual 0?

edited Jul 25 '17 at 14:05

Toby Speight

asked Jul 25 '17 at 14:01

John

6

You cannot. So use `strtof/strtod`. – Eugene Sh. Jul 25 '17 at 14:02
1

While the duplicate mentions `atoi` and the corresponding `strtol`, there is an equal correspondence between `atof` and [`strtof`](http://en.cppreference.com/w/c/string/byte/strtof). – Some programmer dude Jul 25 '17 at 14:07
My suggestion is to use `sscanf` instead, e.g.: `res = sscanf(str, "%f", &data);` and then check `if( res != 1)` – VolAnd Jul 25 '17 at 14:08
sorry what is the &data for? – John Jul 25 '17 at 14:13

0 Answers0