Simple fundamental of quantum computing is that, as per wave particle duality in quantum physics a matter can occupy a wave nature or particle nature depends upon the experiment we carried out with it. Same analogy with quantum computer in classical sense the memory-field of a computer is either filled up by '0' or by '1'. But in quantum computing both memory states can be occupied simultaneously. Such computers are very fast to perform an operation than classical computer like in normal cases. Google search engine took 0.10- 0.25 seconds to find out any web page with any keyword. But if quantum algorithms are implemented- this time will change into micro-seconds and will require much less memory than it is now. But this area is under vast research and no such computer is developed so far, but in near future we may succeed.