Namespaces in general help keep code organised and ultimately avoid polluting the global namespace. That is, multiple namespaces can use the same names for different purposes without causing name-clashes. A class, struct or union is also a namespace.
The std namespace contains all standard library names, including standard template library names. The namespace is also subdivided to separate different features of the library.
Although namespaces can make code less readable, you can import names into the global namespace to help simplify code without polluting the global namespace. This is achieved by importing names locally, within those functions and classes that specifically require those names. In trivial programs, it is common practice to import all standard library names into the global namespace but in real-world programs imports are highly localised.
No, the use of 'namespace std' is not compulsory. You can specifiy it on any object reference. Specifying 'namespace' simply provides a default value. Contrast ... using namespace std; cout << "Hello world!" << endl; ... with ... std::cout << "Hello world!" << std::endl;
If you do not include the directive using namespace stdin your program, any references to objects in namespace std will need be be qualified with that namespace. For instance...cout
No. You can't use namespace std even if you include stdio.h. At the very least you must include stddef.h before you can use namespace std.
#include <iostream> using namespace std;
A quick and simple way to do this would be to add 'std::' directly in front of the data type that requires it. For example: a vector data type, without the line of code 'using namespace std' would look like this: 'std::vector' (without the inverted commas).
A namespace is similar to a class in object oriented programming. A namespace contains functions defined by the programmer. for example namespace std contains functions like cout and cin.namespaces can be globaly declared like so: "using namespace std;"which includes all the functions located in the namespace std.if you only need to use cout you can globaly declare only cout like this "using std::cout;"orstd::cout
#include <iostream> using standard namespace std; int main() { cout << "your prob shouldn't be taking c++"; return 0; }
Here's one: there's no namespace in C
#include<iostream> int main() { using namespace std; cout<<"Hello world!"<<endl; return( 0 ); }
cin is an object........ An Example is // By Codex #include <iostream> using namespace std; int main(){ int age; cout << "How Old Are You?\n"; cin >> age; cout << "You are << age << years old\n"; system("pause") return 0; }
The std namespace is the standard library, which includes many of the common data types, constants, structures, classes and functions that you will use to create C++ programs. There are very few non-trivial C++ programs that do no make use of at least some portion of the standard library at some point. Note that you need only include those portions you actually use; there is no need to include the entire standard library. Any built-in functions that require the standard library will include only as much as they need to, whether you yourself include those portions or not.
#include<iostream> int main() { using namespace std; cout<<"Hello world!"<<endl; return(0); }