The user will input 15 different integer numbers. Your program will find if the input number is already existing or in put no

Answer 1

Are you sure you really want to solve this task?

I wonder because you neither tagged the relevant programming language, nor presented your own attempt to show efforts, nor did you notice that the text got cut off in the heading.

Answer 2

We can't help if we don't know what language you need for this task.

In most language you take input, then check some list/array, if input is in array you already have this number, if not then you add this new number to this array.

Also it is much better for you to place your code attempt, because we can tell you, where you make mistake and help you to don't repeat it, and to understand why something don't work and how to make it work.