Call By Value Vs Call By Reference

Call By Value	Call By Reference
In this, the function is called by passing value of variable as argument.	In this, the function is called by passing address of variable as argument.
Arguments passed by value can be variables, literals or expressions.	Arguments passed by reference can only be variables.
In this, copy of actual arguments is created and passed to function.	In this, no copy of actual arguments is created.
Actual and formal arguments are created in different memory locations.	Actual and formal arguments are created in same memory locations.
Any changes made to the formal arguments will have no effect on actual arguments.	Any changes made to the formal arguments will have immediate effect on actual arguments.
No pointers are used in this approach.	The pointers are used in this approach.
It is a slow way of calling functions.	It is a fast way of calling functions.
Program: #include<iostream> using namespace std; int swap(int, int); int main() { int a=4, b=10; cout<<"Before Swaping:"; cout<<"\nValue of a="<<a<<" & b="<<b; swap(a,b); return 0; } int swap(int x, int y) { int temp; temp=x; x=y; y=temp; cout<<"\nAfter Swaping"; cout<<"\nValue Of a="<<x<<" & b="<<y; }	Program: #include<iostream> using namespace std; int swap(int *, int *); int main() { int a=4, b=10; cout<<"Before Swaping:"; cout<<"\nValue of a="<<a<<" & b="<<b; swap(&a,&b); return 0; } int swap(int *x, int *y) { int temp; temp=*x; *x=*y; *y=temp; cout<<"\nAfter Swaping"; cout<<"\nValue Of a="<<*x<<" & b="<<*y; }