OOP C++ IOE NOTE NCE NOTE

C++ IOE Computer Electrical OOP Note for final exam for 32 Mark conform

Inline function: 

It is the function that is expanded inline when it is called with corresponding code. The syntax for making inline is inline return-type function-name(no arguments/arguments) 

Note:- inline function should always have return type.

Advantage: 

• It reduces the exception time of a program with function having fewer lines of codes.

Disadvantage: 

• The execution time of inline function is more than normal function if the function has the larger number of codes or more lines of code. 
• It does not work for the recursive course. 

Default Arguments:

 C++ allows programmers to call a function without specifying all its arguments. In such case function assigned a default value to the parameters which does not have matching arguments in function call. These value in function definition are called default arguments. 

Note: while assigning a default value , we should place the default from right to left. 

eg:- 

• float simple (int P, int t, float r=0.15) (default argumernt or legal) 
• float simple(int p, int t=2,float r) (illegal) 
• float simple(int p, int t=2,float r=0.15) (legal) 

Inline and default arguments: 

function overloading:

function overloading means using same function name to perform variety of task. But in function overloading we must consider two things. They are:

• 1.       Either the number of arguments in function should be different (the number of input to function should vary).
• 2.       if the number of arguments are same then the data type of the function arguments should be different number of parameter  different.

Note: return type has no role in function overloading

int sum(int a, int b)

{

return (a+b);

}

int sum(int a1, int b1, int c1)

{

return(a1+b1+c1);

}

int sum(int d)

{

return (d+5);

}

void main()

{

cout<<"The sum of one variable"<<sum(10)<<endl;

cout<<"The sum of two variable"<<sum(10,20)<<endl;

cout<<"The sum of three vriable"<<sum(10,20,30)<<endl;

getch();

}

Q. write a program to calculate the area of rectangle and triangle using concept of function overloading.

type II

#include<iostream.h>

#include<conio.h>

using namespace std;

int area(int l, int b)

{

return (l*b)

}

float area(int b, float h)

{

return (0.5*b*h);

}

void main()

{

int l1,b1;

float  h;

cout<<"Enter the value of l1,b1 & h1<<endl;

cin>>l1>>b1>>h1;

cout<<"The area of rectangle is <<area(l1,b1)<<endl;

cout<<"The area of triangle is<<area(l1,h1);

getch();

}

 Reference variable:

Ans:  Is an alternative name given to the original variable. any changes made to reference variable will change original variable and vice versa.

the syntax for making reference variable is:-

data-type & reference_variable = original variable

eg:- int &a(reference variable)=X(original variable)

#include<iostream.h>

#include<conio.h>

using namespace std;

void main()

{

int x=5;

int &a=x; // making refrance variable

a=a+5;

cout<<"The value of x is"<<x<<endl;

getch();

}

output =10

                            

Q. is the concept of alternative variable used for pass by reference ? if yes show with an appropriate example.

Ans: pass by reference: provision of reference variable in c++ allows us to pass parameter to the function by reference. when we pass argument by reference the formal argument in the function call (the input variable of function definition) becomes alternative variable ( or reference variable) of the variable in function call.

#include<iostream.h>

#include<conio.h>

using namespace std;

void swap (int &a, &b)

{

int temp=a;

a=b;

b=temp;

}

void main()

{

int x1=5,y1=6;

cout<<"before swapping x1="<<x1<<endl<<"y1="<<y1<<endl;

swap(x1,y1);    // function call

cout<<"After swapping"<<"x1="<<x1<<endl<<"y1"<<y1<<endl;

getch();

} 

Q. wap to calculate area and perimeter of rectangle in a function and display the result in main().

#include<iostream.h>

#include<conio.h>

using namespace std;

void rectangle(int l, int b, int &A1, int &P1)

{

A1=l*b;

P1=2*(l+b);

}

void main()

{

int l1,b1,A,P;

cout<<"Enter the value of l1 and b1"<<endl;

cin>>l1>>b1;

rectangle (l1,b1,A,P);

cout<<"Area of rectangle is "<<A<<endl<<"Perimeter of rectangle is"<<P<<endl;

getch();

}

 

Return by reference: 

In return by reference in true case c++ assign a reference value . in return by the function is called as:

syntax: function call = reference value;

eg:-

Max(a,b)=200; (reference value  )

the syntax for function definition in return by reference is

return-type & function_name(data_type1 & variable1,data type2 and variable 2...... upto n)

example of return by reference:

 #include<iostream.h>

#include<conio.h>

using namespace std;

int &Max(int &a, int &b)

{

if (a>b);

{

return (a);

}

else

            {

            return (b);

            }

}

void main()

{

int a=10, b=5;

Max(a,b)=200;  // function call

cout<<"a="<<a<<endl<<"b="<<b<<endl;

getch();

}

output: a=10, b=5

Q. How memory is allocated dynamically for normal variable and array?

Ans: Memory is allocated dynamically for normal variable by using syntax:-

pointer-variable = new data type

eg:-

int *p;

p=new int;

alternatively we can combine to allocate dynamically

syntax: data-type *pointer variable = new data type

 

for array

syntax

data type *pointer = new data type (size)

eg:-

int *p = new int [20];

 

class and object:

class:

• 1.       a class is a way to bind data and associated function together.
• 2.       it allows data and function to hidden if necessary for external use.
• 3.       defining a class means creating a user defined data type that behaves as built in data.
• 4.       once a class has been declared we can create any number of object belonging to that class.

syntax:

class class_name

{

private:

data member;

member function;

public:

data member;

member function;

};          //end of class

 

Generally data are placed in private section and function are placed in public section.

• 5.       class contains both data and function . Data are called data member and function are called member function.
• 6.       data and function are defined in private section are not accessible out of the class.
• 7.       data and function placed in public section are only accessible from outside the class.
• 8.       the word private is optional . the data in function of class by default private.

object:

• ð  object are the basic entities of oop. the object may be person place or anything's that have some physical attribute. Object are the variable of class in terms of programming.

syntax:

class_name objects_name(variable name)