Defination:
giving synonym to the existing variable is called reference variable.
Example:
int a=5;
int &b=a;
List the uses of references.
Ans:
Ans: /*see the notes for advantages of reference variable. This question is most frequently asked question in Interviews >
1) Fast Execution 2) Saving Memory 3) We can avoid the pointers 4) duplication is avoided
5) No complexity
Where do we use Reference?
when you have to pass a class object as an argument to any function. when you want to modify the data in the calling function through called function. 2) in copy constructor
#include <iostream>
#include<conio.h>
void swap(int &a, int &b)
{
int temp = 0;
temp = a;
a = b;
b = temp;
return;
}
void main()
{
int a = 10;
int b = 20;
cout<< "\na = "<< a <<"\n"<<"b = "<<b<<"\n";
swap(a,b);
cout<< "After swap";
cout<< "\na = "<< a <<"\n"<<"b = "<<b<<"\n";
}
same program using Pointers
#include <iostream.h>
#include<conio.h>
void swap(int *a, int *b)
{
int temp = 0;
temp = *a;
*a = *b;
*b = temp;
}
void main()
{
int a = 10;
int b = 20;
cout<< "\na = "<< a <<"\n"<<"b = "<<b<<"\n";
swap(&a,&b);
cout<< "After swap";
cout<< "\na = "<< a <<"\n"<<"b = "<<b<<"\n";
getch();
}
some points about reference variable:
- Do not initialize a reference variable with a constant value. This means int &var = 10 is not a valid initialization.
- Do not return a reference from a function as the memory address that is referred by the reference variable would scope out once the function is done it’s execution.
- Avoid using references to variables whose memory are dynamically allocated as it might create unnecessary confusion regarding the clean-up of that memory.plexity (6) It allows parameter to be changed .
