I. Functions in C++
A function is a block of code that performs a specific task.
It helps in code reusability, modularity, and readability.
General Syntax
Copy code
Cpp
return_type function_name(parameters)
{
// statements
}
1. Inline Functions
An inline function is a function whose function call is replaced by the function code itself during compilation.
Purpose
Avoids function call overhead
Increases execution speed
Used for small functions
Syntax
Copy code
Cpp
inline return_type function_name(parameters)
Example
Copy code
Cpp
#include <iostream>
using namespace std;
inline int square(int x)
{
return x * x;
}
int main()
{
cout << square(5);
return 0;
}
Advantage
✔ Faster execution
Limitation
❌ Not suitable for large functions
2. Function Overloading
Function overloading allows multiple functions with the same name but different parameters.
Purpose
Improves code clarity
Implements compile-time polymorphism
Rules
Functions must differ in:
Number of arguments
Type of arguments
(Return type alone is NOT enough)
Example
Copy code
Cpp
#include <iostream>
using namespace std;
int add(int a, int b)
{
return a + b;
}
float add(float a, float b)
{
return a + b;
}
int main()
{
cout << add(10, 20) << endl;
cout << add(2.5f, 3.5f);
return 0;
}
II. Classes and Objects
Class
A class is a blueprint that contains data members and member functions.
Object
An object is an instance of a class.
1. Declaring Objects
Syntax
Copy code
Cpp
class_name object_name;
Example
Copy code
Cpp
class Student
{
public:
int roll;
};
Student s1;
2. Defining Member Functions
Member functions can be defined:
Inside the class
Outside the class using scope resolution operator (::)
Example (Outside class)
Copy code
Cpp
#include <iostream>
using namespace std;
class Sample
{
public:
void show();
};
void Sample::show()
{
cout << "Hello C++";
}
int main()
{
Sample s;
s.show();
return 0;
}
3. Static Member Variables and Functions
Static Member Variable
Shared by all objects
Only one copy exists
Static Member Function
Can access only static members
Called using class name
Example
Copy code
Cpp
#include <iostream>
using namespace std;
class Count
{
public:
static int c;
static void show()
{
cout << "Count = " << c;
}
};
int Count::c = 10;
int main()
{
Count::show();
return 0;
}
4. Array of Objects
Used when multiple objects of the same class are needed.
Example
Copy code
Cpp
#include <iostream>
using namespace std;
class Student
{
public:
int roll;
};
int main()
{
Student s[3];
s[0].roll = 101;
s[1].roll = 102;
s[2].roll = 103;
for(int i=0;i<3;i++)
cout << s[i].roll << endl;
return 0;
}
5. Friend Functions
A friend function can access private and protected members of a class.
Purpose
Allows external function to access class data
Example
Copy code
Cpp
#include <iostream>
using namespace std;
class Sample
{
private:
int x;
public:
Sample()
{
x = 10;
}
friend void show(Sample s);
};
void show(Sample s)
{
cout << s.x;
}
int main()
{
Sample s;
show(s);
return 0;
}
6. Overloading Member Functions
Member functions of a class can be overloaded.
Example
Copy code
Cpp
#include <iostream>
using namespace std;
class Demo
{
public:
void display(int a)
{
cout << a << endl;
}
void display(float b)
{
cout << b << endl;
}
};
int main()
{
Demo d;
d.display(10);
d.display(5.5f);
return 0;
}
7. Bit Fields and Classes
Bit fields allow storing data in bits, saving memory.
Syntax
Copy code
Cpp
data_type variable : size;
Example
Copy code
Cpp
#include <iostream>
using namespace std;
class Flags
{
public:
unsigned int a : 1;
unsigned int b : 1;
};
int main()
{
Flags f;
f.a = 1;
f.b = 0;
cout << f.a << " " << f.b;
return 0;
}
8. Constructor and Destructor with Static Members
Constructor
Called automatically when object is created
Destructor
Called when object is destroyed
Example
Copy code
Cpp
#include <iostream>
using namespace std;
class Test
{
public:
static int count;
Test()
{
count++;
cout << "Object Created: " << count << endl;
}
~Test()
{
cout << "Object Destroyed" << endl;
}
};
int Test::count = 0;
int main()
{
Test t1, t2;
return 0;
}
⭐ Importance (Why We Use These Concepts)
Concept
Purpose
Inline function
Faster execution
Function overloading
Code clarity & polymorphism
Class & object
Real-world modeling
Static members
Shared data
Friend function
Controlled data access
Array of objects
Handle multiple objects
Bit fields
Memory optimization
Constructor & destructor
Resource management
No comments:
Post a Comment