testing a number's quare root is an integer and casting to a value?

[madscijr]

I need to test whether a number's square root is an integer (nothing after the decimal, test code below). 
My first try was to use MOD and see if 1 divides into it evenly, but MOD is integer only. 
I thought maybe I could cast the square root to an integer, and subtracting that from the square root value yields 0, we know there is a fractional portion left over, so it's not just an integer. 
Did I hear something about a "cast" command being added at some point? 
Even if that's not the best way to test the square root, that would be good to know about. 
Any guidance would be appreciated... 

Code: (Select All)

Dim iLoop%
For iLoop% = 1 To 16
    TestSquareRoot iLoop%
Next iLoop%

Sub TestSquareRoot (MyNumber%)
    Dim MySquareRoot!
    MySquareRoot! = Sqr(MyNumber%)
    Print "For value " + _Trim$(Str$(MyNumber%)) + ", " + _
        "square root is " + _trim$(str$(MySquareRoot!)) + ", " + _
        _IIf((MySquareRoot! Mod 1 = 0), "even", "different")
End Sub

[SMcNeill]

If num = INT(num) THEN it's an integer

[madscijr]

If num = INT(num) THEN it's an integer

Thank you sir, that's so simple, I love it.

[Pete]

Just don't ever get caught by variable type precision limits...

num = 5542534534534534534534532453453454534534.5 ' Number too big for variable type.
Print InStr(Str$(num), ".") ' Fails.
If num = Int(num) Then Print "Integer" 'Fails

Pete

[Jack]

testing a number's quare root is an integer and casting to a value? 

@madscijr
the question is a bit fuzzy to me, I thought you were asking whether a given square-root of a number was an integer
I haven't tested whether  the sqr function gives exact square-roots of numbers which square-root is an integer

[bplus]

What is Mod 1 ?

Code: (Select All)

For i = 1 To 10

    MySquareRoot! = Sqr(i)

    Print i, MySquareRoot!, MySquareRoot! Mod 1, _IIf((MySquareRoot! Mod 1 = 0), "Integer", "Not Integer")
Next

looks like mod 1 = 0 for everything!

I give the testing of a number as an integer with Mod 1, a mod 1 rating.


From Wiki:

What is mod 1 in math?
The range of values for an integer modulo operation of n is 0 to n − 1. a mod 1 is always 0. When exactly one of a or n is negative, the basic definition breaks down, and programming languages differ in how these values are defined.

[SMcNeill]

Just curious:  Is anyone else's OCD trying to explode at the title of this topic?  QUARE ROOT??!! 

GAAAAAHHHHH!!!!!!

[bplus]

Sounds OK when I read it out loud

[Pete]

Stop quaking about, geeze!

Pete

[madscijr]

testing a number's quare root is an integer and casting to a value? 

@madscijr
the question is a bit fuzzy to me, I thought you were asking whether a given square-root of a number was an integer
I haven't tested whether  the sqr function gives exact square-roots of numbers which square-root is an integer

Yeah, I wanted to find if a number's square root was a straight integer, and thought casting it to an int (or long, just a non-floating point number really), I could then compare it to the actual square root, and see if they're equal. I hadn't tried cast in qb64pe yet but that could be useful for a lot of stuff.

---

Just don't ever get caught by variable type precision limits...

num = 5542534534534534534534532453453454534534.5 ' Number too big for variable type.
Print InStr(Str$(num), ".") ' Fails.
If num = Int(num) Then Print "Integer" 'Fails

Pete

Ha! Yeah, this isn't for really big numbers, integer is good.