Level 1
- Create a class named 'Student' with String variable 'name' and integer variable 'roll_no'. Assign the value of roll_no as '2' and that of name as "John" by creating an object of the class Student.
package com.codesdope;
public class Student {
String name;
int roll_no;
}
public class TestStudent {
public static void main(String[] args) {
Student s = new Student();
s.name = "John";
s.roll_no = 2;
System.out.println("Name is " + s.name + " add roll number is " + s.roll_no);
}
}
- Print the sum, difference and product of two complex numbers by creating a class named 'Complex' with separate methods for each operation whose real and imaginary parts are entered by user.
package com.codesdope;
public class Complex {
int real;
int imag;
public Complex(int r, int i) {
real = r;
imag = i;
}
public static Complex add(Complex a, Complex b) {
return new Complex((a.real + b.real), (a.imag - b.imag));
}
public static Complex diff(Complex a, Complex b) {
return new Complex((a.real - b.real), (a.imag - b.imag));
}
public static Complex product(Complex a, Complex b) {
return new Complex(((a.real * b.real) - (a.imag * b.imag)), ((a.real * b.imag) + (a.imag * b.real)));
}
public void printComplex() {
if (real == 0 && imag != 0) {
System.out.println(imag + "i");
} else if (imag == 0 && real != 0) {
System.out.println(real);
} else {
System.out.println(real + "+" + imag + "i");
}
}
}
public class TestComplex {
public static void main(String[] args) {
Complex c = new Complex(4, 5);
Complex d = new Complex(9, 4);
Complex e = Complex.add(c, d);
Complex f = Complex.diff(c, d);
Complex g = Complex.product(c, d);
e.printComplex();
f.printComplex();
g.printComplex();
}
}
Output
13 + 9i
-5 + 1i
16 + 61i
- Write a program to print the area of a rectangle by creating a class named 'Area' taking the values of its length and breadth as parameters of its constructor and having a method named 'getArea' which returns the area of the rectangle. Length and breadth of rectangle are entered through keyboard.
package com.codesdope;
import java.util.Scanner;
public class Area {
int length;
int breadth;
public Area(int l, int d) {
length = l;
breadth = d;
}
public int getArea() {
return length * breadth;
}
}
public class TestArea {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
int l, b;
System.out.println("Enter length");
l = s.nextInt();
System.out.println("Enter breadth");
b = s.nextInt();
Area a = new Area(l, b);
System.out.println("Area : " + a.getArea());
}
}
- Write a program to print the area of two rectangles having sides (4,5) and (5,8) respectively by creating a class named 'Rectangle' with a method named 'Area' which returns the area and length and breadth passed as parameters to its constructor.
package com.codesdope;
public class Rectangle {
int length;
int breadth;
public Rectangle(int l, int b) {
length = l;
breadth = b;
}
public int getArea() {
return length * breadth;
}
public int getPerimeter() {
return 2 * (length * breadth);
}
}
public class TestRectangle {
public static void main(String[] args) {
Rectangle a = new Rectangle(4, 5);
Rectangle b = new Rectangle(5, 8);
System.out.println("Area : " + a.getArea() + " Perimeter is " + a.getPerimeter());
System.out.println("Area : " + b.getArea() + " Perimeter is " + b.getPerimeter());
}
}
- Write a program to print the area and perimeter of a triangle having sides of 3, 4 and 5 units by creating a class named 'Triangle' without any parameter in its constructor.
public class Triangle {
int a, b, c;
public double getArea() {
double s = (a + b + c) / 2.0;
return Math.pow((s * (s - a) * (s - b) * (s - c)), .5);
}
public double getPerimeter() {
return (a + b + c);
}
}
public class TestTriangle {
public static void main(String[] args) {
Triangle t = new Triangle();
t.a = 2;
t.b = 5;
t.c = 6;
System.out.println(t.getArea());
System.out.println(t.getPerimeter);
}
}
- The Matrix class has methods for each of the following: 1 - get the number of rows 2 - get the number of columns 3 - set the elements of the matrix at given position (i,j) 4 - adding two matrices. If the matrices are not addable, "Matrices cannot be added" will be displayed. 5 - multiplying the two matrices
package com.callicoder;
public class Matrix {
int row;
int column;
int[][] arr;
public Matrix(int r, int c) {
row = r;
column = c;
arr = new int[row][column];
}
public int getRows() {
return row;
}
public int getColumns() {
return column;
}
public int getElement(int r, int c) {
return arr[r][c];
}
public void setElement(int r, int c, int element) {
arr[r][c] = element;
}
public static Matrix add(Matrix x, Matrix y) {
if ((x.row == y.row) && (x.column == y.column)) {
Matrix m = new Matrix(x.row, x.column);
for (int i = 0; i < m.row; i++) {
for (int j = 0; j < m.column; j++) {
m.setElement(i, j, (x.getElement(i, j) + y.getElement(i, j)));
}
}
return m;
} else {
System.out.println("Matrices can not be added");
return new Matrix(0, 0);
}
}
public static Matrix product(Matrix x, Matrix y) {
Matrix m = new Matrix(x.row, y.column);
for (int i = 0; i < x.row; i++) {
for (int j = 0; j < y.column; j++) {
int sum = 0;
for (int k = 0; k < x.column; k++) {
sum = sum + (x.getElement(i, k) * y.getElement(k, j));
}
m.setElement(i, j, sum);
}
}
return m;
}
public void printMatrix() {
System.out.println("Matrix is : ");
for (int i = 0; i < row; i++) {
for (int j = 0; j < column; j++) {
System.out.print(arr[i][j] + " ");
}
System.out.println();
}
}
}
public class TestMatrix {
public static void main(String[] args) {
Matrix m = new Matrix(3, 3);
Matrix n = new Matrix(3, 3);
int k = 1;
for (int i = 0; i < 3; i++) {
for (int j =0; j < 3; j++) {
m.setElement(i, j, k);
k++;
n.setElement(i, j, k);
k++;
}
}
m.printMatrix();
n.printMatrix();
Matrix o = Matrix.add(m, n);
o.printMatrix();
Matrix p = Matrix.product(m, n);
p.printMatrix();
}
}
Output
Matrix is :
1 3 5
7 9 11
13 15 17
Matrix is :
2 4 6
8 10 12
14 16 18
Matrix is :
3 7 11
15 19 23
27 31 35
Matrix is :
96 114 132
240 294 348
384 474 564