What are references in C++?

Programming Language
#1

It is a variable that behaves as an alias for another variable. They are created using the ampersand (&) operator. When we create a variable, then it occupies some memory location. We can create a reference of the variable; therefore, we can access the original variable by using either name of the variable or reference

CODE:

//Example 1
int a=10;  
int &ref=a;  

//Example 2
int a=10;   // 'a' is a variable.  
int &b=a; // 'b' reference to a.  
int &c=a; // 'c' reference to a.
  • Must be initialized during declaration.
  • Cannot be reassigned
  • Can also be passed as a function parameter.

Now let’s see the key differences between references and pointers:-

POINTERS

  • A pointer can be initialized to any value anytime after it is declared.
  • A pointer can be assigned to point to a NULL value.
  • Pointers need to be dereferenced with a *
  • A pointer can be changed to point to any variable of the same type.

REFERENCES

  • A reference must be initialized when it is declared.
  • References cannot be NULL.
  • References can be used ,simply, by name.
  • Once a reference is initialized to a variable, it cannot be changed to refer to a variable object.

In the final topic for this video, we will understand that a function pointer is a pointer used to point functions. It is used to store the address of a function. We can call the function by using the function pointer, or we can also pass the pointer to another function as a parameter.

They are mainly useful for event-driven applications, callbacks, and even storing functions in arrays.

void printname(char *name)  
{  
    std::cout << "Name is :" <<name<< std::endl;  
}  
  
int main()  
{  
    char s[20];  
    void (*ptr)(char*);  // function pointer declaration  
    ptr=printname;  // storing the address of printname in ptr.  
    std::cout << "Enter the name of the person: " << std::endl;  
    cin>>s;  
    cout<<s;  
    ptr(s); 
   return 0;  
}