OOP

1. 1
Object Oriented Programming

2. 2
Contents
• Passing Array to a Function
• Methods of Passing arguments to a Function
• Call by Value
• Call by Reference
• Function Overloading

3. 3
Passing Array to a Function
• When we need to pass large amount of data to a function
as input, then we should pass an array to a function.
• When an array argument is passed to a function, its
starting address is passed to the array parameter in the
function.
• Both parameter and argument refer to the same array.
• The function can change the contents of the array by
directly accessing the memory cells where the array’s
elements are stored.

4. 4
Declaration of Function with Array parameters
• When an array argument is used as an argument of a
function, it is specified in the function declaration.
• Examples:
void add ( int [] );
It is a function with name add, return type of void and
parameter of int array type.
void add (int [][], float [][]);
This function have two parameters .
First parameter is of int two dimensional array type and
second parameter is of float two dimensional array type.

5. 5
Function Definition with Array parameters
• The type and name of the array parameter is specified in the
header of the function definition.
• The type of array in the header must match with the
parameter type in the function declaration.
Example:
void add(int a[])
{
}

6. 6
Calling Function with Array arguments
• When a function having an array parameter is called,
then only the name of the array is given in the function
calling statement.
• Only the memory address of the array argument is
passed to the array parameter in the function definition.

7. 7
Example
This program will define a function that will get an array
and will print the elements of array.

8. 8
void print_arr(int [],int );// Function Declaration
void main() // Calling Function
{
int arr[5] = {10,15,20,25,30};
print_arr(arr,5);
getch();
}
void print_arr(int a[],int size ) // Called Function
a = 100 , size = 5
{
cout<<"Printing elements of arrayn";
for(int i= 0 ;i<size;i++)
{
cout<a[i]<<"t";
}
}

9. 9
Methods of Passing arguments to a Function
• Arguments can be passed to a function in two ways:
1. Call by Value
2. Call by Reference

10. 10
Function Call by Value
• In this approach , when a function is called, the values
of the arguments are passed to the parameters of the
function definition.
• Separate memory areas are reserved for both the
arguments and parameters.
• The function accesses the value in the newly created
variable and the data in the original variable in the
calling function is not changed.

11. 11
Function Call by Reference
• In this approach , when a function is called, the reference of
the argument is passed to the parameter of the function
definition.
• No new copy of the variable is created in the function.
• The original variable is accessed in the function with
reference to the second name or alias.
• Both the arguments and parameters point to the same
memory addresses, so changing the value of parameter also
changes the value of argument.
• The reference parameters are represented by & sign both in
the function declaration and function definition.

12. 12
Example
This program will demonstrate the difference between
Function Call by Value and Call by Reference

13. 13
// Call by Value
void swap(int ,int );// Function Declaration
void main() // Calling Function a b
{
int a = 2, b = 4;
swap(a , b);
cout<<"Value of a and b after swappingn";
cout<<"Value of a : "<<a<<endl; c d
cout<<"Value of b : "<<b<<endl;
}
void swap(int c , int d ) // Called Function temp
{ int temp;
temp = c;
c = d;
d = temp;
}
2
2
4
4
2

14. 14
// Call by Reference
void swap(int & ,int &);// Function Declaration
void main() // Calling Function a(100) b(104)
{
int a = 2, b = 4;
swap(a , b);
cout<<"Value of a and b after swappingn";
cout<<"Value of a : "<<a<<endl; c d
cout<<"Value of b : "<<b<<endl;
}
void swap(int &c , int &d ) // Called Function temp
{ int temp;
temp = c;
c = d;
d = temp;
}
4
104
100
2
2

15. 15
Function Overloading
• Defining two or more functions with the same name but
with different parameter list is known as function
overloading.
• It is used in those situations, where a function needs to
operate on different types of data.
• For example, if we want to add data of different types
such as int, float , double etc.

16. 16
Example
This program will demonstrate the concept of function
overloading.

17. 17
int add(int , int);
double add(double, double);
int add(int, int, int);
void main() // Calling Function
{
cout<<"Sum of 2 integer values"<<add(3,4);
cout<<"Sum of 2 float
values"<<add(3.5,2.5);
cout<<"Sum of 3 int values"<<add(6,4,5);
}
int add(int n1, int n2)
{
return n1+n2;
}
Sum of 2 integer values 7
Sum of 2 float values 6
Sum of 3 int values 15

18. 18
double add(double n1, double n2)
{
return (n1+n2);
}
int add(int n1, int n2, int n3)
{
return (n1+n2+n3);
}