why are we use using namespace space std
header file and when we declare iostream header file let here need for declaration of using namespace header file?
CPP - Basic c++ Concepts
@khemchandrs A namespace is a declarative region that provides a scope to the identifiers (the names of types, functions, variables, etc) inside it. Namespaces are used to organize code into logical groups and to prevent name collisions that can occur especially when your code base includes multiple libraries.
Also refer this: https://www.tutorialspoint.com/What-does-using-namespace-std-mean-in-Cplusplus