Question

C++: How are std::cout << “hello world” and std::cout << “hello” << ‘ ‘ << “world” different?

Answer 1

code:

#include <iostream>

int main()
{
std::cout << "hello world" ;
return 0;
}

Explain:

On compiling the above code, Hello World will be printed on the screen.

Let's start with std::cout << "Hello World"; - std is a namespace and cout is defined in this std namespace.

Here , in this code the space between two words hello and world is already give by user hence space will print automatically.

Basically, a namespace is a special area inside which something is defined. So, in this case, cout is defined in std namespace.

Thus, std::cout states that cout is defined in the std namespace or to use the definition of cout which is defined in std namespace.

So, std::cout is used to use the definition of cout from std namespace.

<< is the output operator.
here << is used to pass "Hello World" to cout. Thus, std::cout << "Hello World"; passes "Hello World" to cout and cout will print this Hello World on the screen.

code:

#include <iostream>

int main()
{
std::cout << "hello" << ' ' << "world" ;
return 0;
}

Explain:

In the above example, std::cout << "hello" << ' ' << "world" ; printed "Hello world" .

Thus, the space between two words hello and world given by user by using <<' ' that's why they seperated from each otherwise user not give space it will print like Helloworld i, e no space will be there .

std::cout << “hello world”	The space is already given in program itself hence the output is Hello world the space is give already between two words hello and world
std::cout << “hello” << ‘ ‘ << “world”	The space is given using << ' ' if the space will not provide using using <<' ' the words will not seperate and print like Helloword But because space is given it print output like Hello world