This presentation is about the inline Function and default arguments in C++.

1. Functions
• A function is a group of statements that together
perform a task.
• main() -> mandatory function =
• Various programs define additional functions.
• A function declaration tells the compiler about a
function's name, return type, and parameters. A
function definition provides the actual body of the
function.

2. Function Declaration
• A function can be defined as:
Syntax : return_type function_name(arguments)
{
body of the function
}
For e.g :
int add(int a,int b)
{
return a+b;
}

3. Calling a Function
• A function can be called
in a main() function or in
other functions.
• When it is called inside
itself than it called as
recursive function.
main()/function_1()
{
body
function(passing values);
}
For e.g :
main()
{
int a,b;
cout<<“Sum=“<<add(a,b);
}
int add(int x,int y)
{
return x+y;
}

4. Inline Functions
• If a function is inline than:
– Compiler puts its code at the place
where it is called at compile time
– To define a function as inline
function
• use the keyword “inline” just
before the return type.
– The compiler ignore the inline
qualifier in case defined function is
more than a line.
inline return_type
function_name(args)
{
//one line code
}

5. Inline Function (example)
#include <iostream>
using namespace std;
inline int Max(int x, int y)
{
return (x > y)? x : y;
}
// Main function for the program
int main( )
{
cout << "Max (20,10): " << Max(20,10) << endl;
cout << "Max (0,200): " << Max(0,200) << endl;
cout << "Max (100,1010): " << Max(100,1010) <<
endl;
return 0;
}
Output:
Max (20,10): 20
Max (0,200): 200
Max (100,1010): 1010

6. Why Inline functions
• Objective of using functions:
– To save memory space, when a
function is likely to be called
many times.
Jumping to a function
Saving the registers
Pushing arguments in to the
stack
Returning to the calling
function
• When a function is small enough
(only one line of code) these
things would be a wastage of
time and resources.

7. Function with Default Arguments
• A default argument is a value
provided in function
declaration that is
automatically assigned by the
compiler if caller of the
function doesn’t provide a
value for the argument with
default value.
return _type f_name (arg1,arg2,arg3=value)
• When a default argument is placed then all the other arguments
after that must be default arguments only.
• That says the default arguments must placed on right most side of
all the arguments collectively

8. Default arguments (example)
int sum(int x, int y, int z=0, int w=0)
{
return (x + y + z + w);
}
int main()
{
cout << sum(10, 15) << endl;
cout << sum(10, 15, 25) << endl;
cout << sum(10, 15, 25, 30) <<
endl;
return 0;
}
Output:
25
50
80

9. Default Arguments
• They may come in handy when some arguments
are having the same values.
– For e.g. Bank interest may remain the same for all
the customers for a particular period of deposit.