Reference Variables in C++
- This concept is used in C++.
- When we create a variable of any data type, we use single identifier to identify that variable.
Example: int i;
- In this case, i is an identifier from which we can access that variable.
- If we want to assign some another name to that same identifier then we can use the reference variable concept from C++.
- A reference variable are such a variable which are refering to already created datatypes.
- A reference variables are the names given to the variable.
- Entry of that another name is in the symbol table.
- We can create a reference variable for any data type.
- As said above reference variables are only another name, due to which memory is not allocated for a reference variable.
- Reference variables are needs to be initialized at the time of declaration.
- We cannot create array of a reference variables.
- Multiple references to the single variable are allowed.
- But same reference variable to multiple variables is not allowed.
- A reference to a reference variable is allowed.
- We cannot create array of a references, because a reference variable does not get any memory.
- But we can create a reference to an array.
//
Example:.
int main()
{
int i=10;
int &f=i;
printf(“%d”,i);
printf(“%d”,f);
return 0;
}
//
int main()
{
int i=10;
int &f=i;
int &d=f;
int &s=d;
//
// Reference to reference variable
//
printf(“%d”,i); //10
printf(“%d”,f); //10
printf(“%d”,d); //10
printf(“%d”,s); //10
return 0;
}
//
int main()
{
int i=10;
int &f=i;
int &d=i;
int &s=i;
//
// Multiple reference to single a variable
//
printf(“%d”,i); //10
printf(“%d”,f); //10
printf(“%d”,d); //10
printf(“%d”,s); //10
return 0;
}
//
int main()
{
// Error
// One reference can not refer to different variables
//
int i=10;
int k=20;
int &f=i;
int &f=k;
return 0;
}
//
//
// We can create a reference variable as a member of a class
// Memory is allocated for it also iside the class
// It must be initialized using the initialization list
//
class demo
{
public:
int i;
int &j;
demo():j(i)
{
i=10;
}
};
int main()
{
demo d;
cout<<d.i;//10
d.j++;
cout<<d.i; //11
cout<<d.j; //11
cout<<sizeof(d); // 8
return 0;
}
//
int main()
{
//
// We can create a reference to an array
//
int a[4]={1,2,3,4};
int (&d)[4] = a;
cout<<a[0]; // 1
cout<<a[1]; // 2
cout<<a[2]; // 3
cout<<a[3]; // 4
cout<<d[0]; // 1
cout<<d[1]; // 2
cout<<d[2]; // 3
cout<<d[3]; // 4
return 0;
}
//
int main()
{
int i=90;
int k=90;
int l=45;
int &f=i;
int &d=k;
int &a=l;
// Error
// We can not create an array of a references
//
int &(c[4]) = {f,d,a};
return 0;
}
//
int main()
{
int i=90;
int k=80;
int l=45;
int &f=i;
int &d=k;
int &a=l;
//
// In this way we can create an array of a references
//
int (c[4]) = {f,d,a};
printf(“%d”,c[0]); // 90
printf(“%d”,c[1]); // 80
printf(“%d”,c[2]); // 45
return 0;
}
//
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