Scope
resolution is an operator(::) which gives access to control the global
variables in-spite of local variables exist.
Syntax:
::variable_name;
Tell me the out of bellow program.
Compile time error. Global variable has not declared.But, You
are trying to print undeclared value.
How to
Create reference to Variable:
1)For
existing variables we can create reference by the following syntax.
2)Variable declaration and initialization need to be at the
same place.
The following syntax is invalid. Because Variable declaration
and initialization are not at the same place.
3)We can
give reference to any number of variables. At this instant the addresses for
all remains same.
5) we can’t
refer the constants.
6) we can’t
change references from one variable to another variable.
7)we can
change address of pointer variable through references
8) Referece to
pointers:
9) Array of references and array of pointers possible. But reference
of references is not possible.
Example program
to perform various arithmetic calculations.
Rules
for reference variables:
1)we can’t
change the reference.
2)declaration
at one place, initialization at some other place is not possible.
int x=100;
int *p=&x;
int &y=*p; //valid
int &y=100; //not valid
3)array of
pointers possible, array of references possible, array of addresses possible.
4)references
for int,float,char is possible. References for pointers also possible
Benefits
of reference variables:
1)It gives
simplicity.
2) by using
reference operator,we can refer address of one function variable to address of
another function(calling function).
3) it is
possible to make changes to the original function data by using reference
operator instead of passing address of variable.
