Namespaces in C++ are used to organize too many classes so that it can be easy to handle the application.
For accessing the class of a namespace, we need to use namespacename::classname. We can use using keyword so that we don't have to use complete name all the time.
In C++, global namespace is the root namespace. The global::std will always refer to the namespace "std" of C++ Framework.
C++ namespace Example
Let's see the simple example of namespace which include variable and functions.
#include <iostream>
using namespace std;
namespace First {
void sayHello() {
cout<<"Hello First Namespace"<<endl;
}
}
namespace Second {
void sayHello() {
cout<<"Hello Second Namespace"<<endl;
}
}
int main()
{
First::sayHello();
Second::sayHello();
return 0;
}
Output:
Hello First Namespace
Hello Second Namespace
C++ namespace example: by using keyword Let's see another example of namespace where we are using "using" keyword so that we don't have to use complete name for accessing a namespace program.
#include <iostream>
using namespace std;
namespace First{
void sayHello(){
cout << "Hello First Namespace" << endl;
}
}
namespace Second{
void sayHello(){
cout << "Hello Second Namespace" << endl;
}
}
using namespace First;
int main () {
sayHello();
return 0;
}
