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**ochoapigo****Member**- Registered: 27-Apr-2018
- Posts: 19

Hi, I need help, how can compare numbers negatives in lenguaje scol?

For example:

let atof "$9" -> x in

let " " -> temp_x in

if x =. -255.0 then

(

set temp_x = ftoa(-1.0)

)

else(

set temp_x = ftoa(0.0)

)

This, show error in console.

Thanks so much

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Hi !

Several errors in your code.

You should **never** compare floats in this way, in Scol nor any other language.

To compare two integers, it's ok :

```
if integer1 == integer2 then
...
```

To compare two floats, you compare the difference with an epsilon whose accuracy you arbitrarily choose.

```
if (float1 -. float2) <. epsilon then
_fooS "they are equals"
else
_fooS "They are not equals";
```

You should use the float Scol library : http://redmine.scolring.org/projects/li … float.html (doc)

Your code could be this in h/a.pkg :

```
fun main()=
_showconsole;
let atof "$9" -> x in
let " " -> temp_x in
if std_fCmp x (-.255.0) then
set temp_x = ftoa (-.1.0)
else
set temp_x = ftoa 0.0;;
```

Called by a such script :

```
_load "lib/std/float.pkg"
_load "h/a.pkg"
main
```

I use std_fCmp function. By default, epsilon is 0.000001.

You write :

`if x =. -255.0 then`

Also, = sets a value to a variable, so if x = 255.0 then sets 255.0 to x and the expression tests the return value of set, a side effect. This is an equivalent of if set x = 255.0 then ...

if x =. 255.0 then, with a point, create a syntax error : this is no sense in Scol. It's contrary to its grammar.

In a test, you must double the equal sign but with the float numbers, this is wrong (see above).

Next, -255.0 is wrong. Indeed, - (without point) expects an integer.

-. (with point) expects an float, thus (-.255.0) is correct.

If you want compare an integer and a flot, you must convert the integer to float (or the other way around but your can lost the precision)

Then, your variable named x is stange :

`let atof "$9" -> x in `

will always give 0.000000. I guess you wish to get the value of $9, maybe a parameter into a string ?

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