Are STL string too slower than the old-fashioned null terminated character strings??
yes. But C strings are much more cumbersome to use in some instances. It's more important that you're not using cin and cout.
okaythanx for the quick reply and what about using new node() instead of mallocis new node() also too slow??
That depends on what you mean by node()
Generally allocating memory on the fly is costly. If it cannot be avoided then it will be ok.