Chapter 3 Object Oriented Programming using C++

2nd year Computer science (ICS) Chapter 3 Object Oriented Programming using C++ for Grade-12 Khyber Pakhtunkhwa Board.

Object Oriented Programming using C++ for kpk board

Q.5) Pick that variable from the following list which is improperly declared and named. Also, describe the reason of its invalidity.

• 1) int sum;
• 2) int cats=5, dogs=5;
• 3) int my variable name;
• 4) int void= 5;
• 6) int 3some;
• 7) int meters_of_pipe;
• 8) int length , width=5;

Answer:
Following are the variables which are improperly declared and named.

• int my variable name;
  Reason:
  It is having the spaces between the names.
• int void= 5;
  Reason:
  Reserved or keywords cannot be used as the variable names.
• int 3some;
  Reason:
  A variable name starting with an integer is not valid.

Q.6) Write a C++ program to get six subject marks of a student and then calculate its total, average, and percentage and display them on screen.

Answer:
#include <stdio.h>
void main() {
    int subj1, subj2, subj3, subj4, subj5, subj6;
    float total, average, percentage;
    cout << “Enter marks of the following Subjects (Max: 200)” << endl;
    cout << “————————————————–” << endl;
    cout << “Subject # 01” << endl;
    cin >> subj1;
    cout << “Subject # 02” << endl;
    cin >> subj2;
    cout << “Subject # 03” << endl;
    cin >> subj3;
    cout << “Subject # 04” << endl;
    cin >> subj4;
    cout << “Subject # 05” << endl;
    cin >> subj5;
    cout << “Subject # 06” << endl;
    cin >> subj6;
    total = subj1 + subj2 + subj3 + subj4 + subj5 + subj6;
    average = total / 6;
    percentage = 100 * (total / 1200);
    cout << “The total marks of the student = ” << total << endl;
    cout << “The Average marks of the student = ” << average << endl;
    cout << “The Percentage of the student = ” << percentage << endl;
}
OUTPUT:
The output of the program is as follows:

Q.7) Write a C++ program to find out maximum value out of three integers using conditional operator.

KPK Grade 12 Computer Science Notes

Answer:
void main() {
    int number1, number2, number3;
    cout << “PROGRAM TO PRINT MAXIMUM OF THREE NUMBERS” << endl;
    cout << “—————————————–” << endl;
    cout << “Enter First Number : ” << endl;’
    cin >> number1;
    cout << “Enter Second Number : ” << endl;
    cin >> number2;
    cout << “Enter Third Number : ” << endl;
    cin >> number3;
    if (number1 > number2 && number1 > number3)
    {
        cout << “The maximum number is: ” << number1 << endl;
    }
    if (number2 > number1 && number2 > number3)
    {
        cout << “The maximum number is: ” << number2 << endl;
    }
    if (number3 > number1 && number3 > number2)
    {
        cout << “The maximum number is: ” << number3 << endl;
    }
}
OUTPUT:
The output of the program is as follows:

Q.8) Write a C++ program to find  out the roots of a quadretic equation.

Answer:
#include “stdafx.h”
#include <iostream>  
#include <iostream>
#include <cmath>
using namespace std;
int main() {
        float a, b, c, x1, x2, discriminant, realPart, imaginaryPart;’
        cout << “Enter coefficients a, b and c: “;’
        cin >> a >> b >> c;
        discriminant = b*b – 4 * a*c;
        if (discriminant > 0) {
            x1 = (-b + sqrt(discriminant)) / (2 * a);
            x2 = (-b – sqrt(discriminant)) / (2 * a);
            cout << “Roots are real and different.” << endl;
            cout << “x1 = ” << x1 << endl;
            cout << “x2 = ” << x2 << endl;
}
else if (discriminant == 0)
{
    cout << “Roots are real and same.” << endl;
    x1 = (-b + sqrt(discriminant)) / (2 * a);
    cout << “x1 = x2 =” << x1 << endl;
}
else
{
    realPart = -b / (2 * a);

    imaginaryPart = sqrt(-discriminant) / (2 * a);
    cout << “Roots are complex and different.” << endl;
   cout << “x1 = ” << realPart << “+” << imaginaryPart << “i” << endl;
    cout << “x2 = ” << realPart << “-” << imaginaryPart << “i” << endl;
}
return 0;
}
OUTPUT:
The ouptut of the progarm is as follows

Q.9) Write a C++ program to find out the area of rectangle and display the result on the screen

Answer:
#include “stdafx.h”
#include <iostream>
#include<conio.h>
using namespace std;
void rectangle(int length, int width)
{
    int area;
    area = length*width;
    cout << “Area of Rectangle is = ” << area << “\n\n”;
}
int main()//main program
{
    int L, W;
    cout << “Enter LENGTH of rectangle : “;
    cin >> L;
    cout << “Enter WIDTH of rectangle : “;
    cin >> W;
    rectangle(L, W);
    return 0;
}
OUTPUT:
The output of the program is as follows:

Q.10) Write a C++ program to get the age of a student from the user at run time and display it on the screen.

Answer:
#include <stdio.h>
void main() {
    int birthmonth, birthyear;
    int currentmonth, currentyear;
    int agey, agem;
    cout << “\t\t — PROGRAM TO GET AGE –\n\n”;
    cout << “Enter Your Birth Year(Eg:1989):”;
    cin >> birthyear;
    cout << “\n\nEnter Your Birth Month(Eg:7):”;
    cin >> birthmonth;
    cout << “\nEnter The Current Month(Eg:7):”;
    cin >> currentmonth;
    cout << “\nEnter The Current Year(Eg:2010):”;
    cin >> currentyear;
    agey = currentyear – birthyear;
    agem = 12 – birthmonth;
    cout << “\n\n\t\tYour Age is ” << agey << ” Years And ” << agem << ” Months “;
    _getch();
}
OUTPUT:
The output of the program is as follows:

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