When you write program then there are lots of function and variables used to store value on execution time. So how can you define variable or function in such a way that when execution over then it will release memory storage automatically. Answer is C storage, here you can define function or variable scope either it can be global (life time) or just local (execution time only). Following are the storage classes which can be used to define scope of variable and function: • Auto • Register • Static • Extern