How to compare two very large number

given two integers a and (0 <= a,b <=100^100).

If a is bigger, print "a is bigger than b"

If b is bigger, print "b is bigger than a"

Else, print "They are equal"

I don't exactly know how to solve this problem when the range is upto 100^100. Is there any fine method to solve this problem in C++ ?