How to get 20 digits decimal ?

Hi to all,
how to get 20 digits decimal number using String?After get 20 digits decimal number i have to separate as 8 digits ,6 digits ,6 digits,(8+6+6 = 20 digits) and store in separate strings ?????
Example 20 digit number: 12345678914725836945
A=12345678(8 digits)
B=914725(6 digits)
C=836945(6 digits)
thanks in advance..

It is entirely unclear what your question is.

Are you asking how to split a 20 character string into three strings of fixed length, or are you asking how to form a 20 character string from the the strings A, B, C, or something else altogether?

Perhaps your current attempt in code might clarify what you are trying to do.

get 20 digit decimal means u want it using scanf????
then u take input in loop.
to divide it u can use scrncpy function.