Explain :: operator with an example.
:: Operator : - ‘::’ is known as Scope Resolution Operator. C++ is a block structured language. Different program modules are written in various blocks.
- Same variable name can be used in different blocks. Scope of a variable extends from the point of declaration to the end of the block.
- A variable declared inside a block is ‘local’ variable. Blocks in C++ are often nested.
-
Example :….
….
{
int x = 10;
….
….
{
int x = 20;
…..
….
}
….
}
- The declaration of the inner block hides the declaration of same variable in outer block. This means, within the inner block, the variable x will refer to the data object declared therein. To access the global version of the variable, C++ provides scope resolution operator.
- In the above example, x has a value of 20 but ::x has value 10.
- Similarly, this operator is used when a member function is defined outside the class.
-
Example :Class MyClass
{
int n1, n2;
public:
{
void func1(); ---------Function Declaration
}
};
public void MyClass::func1() ---Use of Scope Resolution Operator to write
function definition outside class definition
{
// Function Code
}
When do you use :: Operator in C++?
- :: is the scope resolution operator. When local variable and global variable are having same name, local variable gets the priority. C++ allows flexibility of accessing both the variables through a scope resolution operator.
