How to store 15 digit number in C++

[RITESHKAKKAR]

hello
how to store 15 digit number in C++

[laserlight]

It depends on what you plan to do with it. If you are storing say, a phone number, then although it is a "number" it is really just text, so store it in a string. If you are storing it to do mathematical computations, then maybe a long long or unsigned long long will work, or maybe because intermediate results might not be in the range of a long long or unsigned long long, or because you have to support implementations in which these are not available, you may need to use a bignum library like GMP or write your own.