Hi everyone....I just need some help...I m beginner in C++ Language. I have to submit a small project. In that project I have to make any small software, application or game. Please help me what should I do???

I would make a simple game.
If the game is text based, you could do something like tic-tac-toe.
If you really want to go for it, you could do a console version of space invaders, but this may be too challenging for a first project.

If the programs have to be graphical, I would recommend making a clone of an arcade game with Allegro.
http://www.cppgameprogramming.com/cgi/nav.cgi?page=index
(Double-click anywhere on the site to bring up the menu).

Something that avoids all the graphical stuff, [Well use an external program - not part of the project] is a simulation. That can go from easy, to extremely complex. There are a number of classes of simulation, but it is easier to give an example, what about a set of stars in an galaxy. You obviously have [initially], very simple equations of motion. You can simulate just a few stars. You might like to simulate the expected constellations patterns in 50,000 years, or small scale like a simulation of our solar system.

Then you can take you project into a number of interesting directions, you can add relativity, you can add solar aging (mass of the start decreased), you can add the effect of a supernova, mass is ejected very fast, energy is ejected at speed of light. You might want to simulate a solar system, that again can get complex, with solar winds, thermal pressure, planet+solar spin, comets etc, or stay simple with just basic F=ma motion.

If you don't want to play with gravity, e.g. a pool simulation [game with 15 ball + white ball] etc, starts very very simple, gets very complex very quickly [spin,
table nap, cushions]

Almost every simulation of a system that has definate state, starts relatively simple but has underlying complexity, even the simple Newtonian star system, with three stars, is actually chaotic in many configurations, and can be enriched, until you have no more time, etc. Effort can be put into runtime optimization, complex physics, size, pretty graphical representation, interesting underlying pattern recognition etc, [e.g. looking for the strange attractors in a fractal system]

There are also simulations in e.g. electrical circuits, heat flow system, atmospherics, etc. Many start simple. :) If you don't want to go down a deterministic simulations, there are many random simulations, e.g. Poker and other card games, etc. Statistical sampling and pattern recognition.

What we are missing to answer you question is, how long have you got. Any extras you can bring to the table, e.g. have you coded half a dozen other languages before, do you have a PhD in quantum physics etc. [and are you interested in exploiting those skills]