How to Declare Extremely Large Integers in Fortran 90?

[Sadjad]

Dear all,

I have a problem with Fortran 90. I want to declare an integer which is enable to support till numbers such as Avogadro number (6.022*10**23). I use "Microsoft Fortran PowerStation 4.0". Can anyone can help me please?

Regards,

 

[Redbelly98]

I've never heard of any language that supports integer variables that high. You could probably write some routine where the digits are stored in many separate long-integer variable types.

But a question is, why not just work in terms of moles, so that you don't need such large numbers?

 

[Dale]

Wikipedia can help. Look at the http://en.wikipedia.org/wiki/Bignum" page.

 

[ceptimus]

What is the point of storing Avagadro's number as an integer? We only know the first 8 digits accurately, so you will have fifteen zeros trailing after those digits.

Languages like java, php, C# have a biginteger class that supports such large numbers, but I don't know about Fortran. You could write your own biginteger functions which would be interesting and instructive though. :)

 

[Tacomablack]

I've never heard of any language that supports integer variables that high. You could probably write some routine where the digits are stored in many separate long-integer variable types.

But a question is, why not just work in terms of moles, so that you don't need such large numbers?

python handles large numbers natively.

 

[Sadjad]

Thank you to all,

To Redbelly98: I have to work with molecules, since the model which I going to model is on the molecules.

To ceptimus: I am with you. It's better not to declare it as an integer because the reason you mentioned.

 

[Louisa]

I've never heard of any language that supports integer variables that high. You could probably write some routine where the digits are stored in many separate long-integer variable types.

For integers of that size, use IBM's PL/I, which caters for integers less than 10**32.