Java Practice Programs on OOPS Concepts

Author: DevendraCollage

AddThreeNum.class

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+//todo: Write a java program to add three numbers.
+
+public class AddThreeNum {
+    public static void main(String[] args) {
+        int num1 = 10;
+        int num2 = 15;
+        int num3 = 25;
+        System.out.println("The Addition of " + num1 + " + " + num2 + " + " + num3 + " = " + (num1 + num2 + num3));
+    }
+}

AddThreeNum.java

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+//* Practice Set fof Chapter-1 of Java
+
+import java.util.Scanner; //? This for reading input from the user
+
+public class Chapter_1_PS {
+    public static void main(String[] args) {
+        // ? Create object of the scanner class
+        Scanner sc = new Scanner(System.in);
+
+        // ! 1. Write a program to sum three numbers in Java.
+        // ? Get number from the user
+        System.out.print("Enter The Number 1 : ");
+        float n1 = sc.nextFloat();
+        System.out.print("Enter The Number 2 : ");
+        float n2 = sc.nextFloat();
+        System.out.print("Enter The Number 3 : ");
+        float n3 = sc.nextFloat();
+        // ? Perform sum of this three number
+        float sum = n1 + n2 + n3;
+        // ? Display the result
+        System.out.println("The Sum of this three number is : " + sum);
+
+        // ! 2. Write a program to calculate CGPA using marks of three subjects (out of
+        // ! 100)
+        // ? Get the Marks of each subject from the user
+        System.out.print("Enter The Marks of Subject 1 : ");
+        float sub1 = sc.nextFloat();
+        System.out.print("Enter The Marks of Subject 2 : ");
+        float sub2 = sc.nextFloat();
+        System.out.print("Enter The Marks of Subject 3 : ");
+        float sub3 = sc.nextFloat();
+        // ? Calculate the Sum of the marks
+        float sumMarks = sub1 + sub2 + sub3;
+        // ? Find the percentage
+        float percentage = sumMarks / 3;
+        // ? Find out the CGPA
+        float CGPA = percentage / 9.5f;
+        // ? Print all the results
+        System.out.println("Your Total of this : " + sumMarks);
+        System.out.println("Your Percentage is this : " + percentage);
+        System.out.println("Your CGPA is this : " + CGPA);
+
+        // ! 3. Write a Java program that asks the user to enter his/her name and greets
+        // them with “Hello <name>, have a good day” text.
+        // ? Get the name of the user
+        System.out.print("Enter Your Name Here : ");
+        String name = sc.nextLine();
+        // ? greets them with “Hello <name>, have a good day” text
+        System.out.println("Hello " + name + ", have a good day.");
+
+        // ! 4. Write a Java program to convert Kilometers to miles.
+        // ? Get the kilometers from the user
+        System.out.print("Enter The Distance in kilometers : ");
+        int km = sc.nextInt();
+        // ? Convert the kilometers in miles
+        float miles = km * 0.621371f;
+        System.out.println("The kilometers is converted into miles : " + miles);
+
+        // ! 5. Write a Java program to detect whether a number entered by the user is
+        // an integer or not. If it’s an integer, print “It’s An Integer”. If it’s not
+        // ? Get the integer number from the user
+        System.out.print("Enter The Number Here : ");
+        boolean isInteger = sc.hasNextInt();
+        if (isInteger) {
+            System.out.println("Yes, This is an Integer!");
+        } else {
+            System.out.println("No, This is not an Integer!");
+        }
+
+        sc.close();
+    }
+}

Chapter_1_PS.class

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+//* Write a program to calculate the percentage of a given student in the CBSE board exam. His marks from 5 subjects must be taken as input from the keyboard. (Marks are out of 100)
+
+import java.util.Scanner;
+
+public class Exercise_1 {
+    public static void main(String[] args) {
+        // ? Create instance of the Scanner class to use the inbuilt method
+        Scanner sc = new Scanner(System.in);
+
+        // ? Get the Marks of 5 subjects from the user
+        System.out.print("Enter The Marks of 1 Subject : ");
+        float sub1 = sc.nextFloat();
+        System.out.print("Enter The Marks of 2 Subject : ");
+        float sub2 = sc.nextFloat();
+        System.out.print("Enter The Marks of 3 Subject : ");
+        float sub3 = sc.nextFloat();
+        System.out.print("Enter The Marks of 4 Subject : ");
+        float sub4 = sc.nextFloat();
+        System.out.print("Enter The Marks of 5 Subject : ");
+        float sub5 = sc.nextFloat();
+
+        // ? Calculate the total of the student marks
+        float total = sub1 + sub2
+                + sub3 + sub4 + sub5;
+
+        // ? Calculate the percentage of the student marks
+        float percentage = total / 5;
+
+        // ? Print the result to the user screen
+        System.out.println("The Total of the All The Subjects is : " + total);
+        System.out.println("The Percentage Is : " + percentage);
+
+        sc.close();
+    }
+}

Chapter_1_PS.java

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+//todo: First Java Hello World Program to print "hello, world"
+
+public class HelloWorld {
+    public static void main(String[] args) {
+        System.out.println("Hello, world!");
+    }
+}

Exercise_1.class

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+//todo: In Java There are some literals
+//todo: Literals means A constant value which can be assigned to the variable is called as a literal.
+
+public class Literals {
+    public static void main(String[] args) {
+        // ? Integer literal
+        int a = 10;
+        System.out.println(a);
+
+        // ? Character Literal - You can place the character in single quote
+        char b = 'A';
+        System.out.println(b);
+
+        // ? Double Literal - You can specify the d with in the last of the number
+        double c = 154545454d;
+        System.out.println(c);
+
+        // ? Byte Literal
+        byte d = 10;
+        System.out.println(d);
+
+        // ? Float Literal - To Define float literal you need to add f to the end of the
+        // number
+        float e = 10.5f;
+        System.out.println(e);
+
+        // ? Boolean Literal - This will store true of false (default value is false)
+        boolean f = true;
+        System.out.println(f);
+
+        // ? Short Literal - This will store short integer
+        short g = 10;
+        System.out.println(g);
+
+        // ? Long Literal - To Define long literal you need to add l to the end of the
+        // long number
+        long h = 555555555l;
+        System.out.println(h);
+    }
+}

Exercise_1.java

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+//* Introduction to Java Operators
+
+public class Operators {
+    public static void main(String[] args) {
+
+        int a = 10;
+        int b = 2;
+
+        // ! 1. Arithmetic operators
+        // ? Arithmetic operators are used to perform mathematical operations such as
+        // addition, subtraction, multiplication, division, etc.
+        System.out.println(a + b); // * 12
+        System.out.println(a - b); // * 8
+        System.out.println(a * b);// * 20
+        System.out.println(a / b); // * 5
+        System.out.println(a % b); // * remainder of the division (10/2=5), so it is 0
+
+        // ! 2. Comparison operators
+        // ? As the name suggests, these operators are used to compare two operands
+        System.out.println(a == b);// * false
+        System.out.println(a != b); // * true
+        System.out.println(a > b); // * true
+        System.out.println(a < b); // * false
+        System.out.println(a >= b); // * true
+        System.out.println(a <= b); // * false
+
+        // ! 3. Logical operators
+        // ? These operators determine the logic in an expression containing two or more
+        // values of variable
+        System.out.println(a == b && b == a); // * false
+        System.out.println(a == b || b == a); // * true
+
+        // ! 4. Bitwise operators
+        // ? Bitwise operators perform the operations on every bit of a number
+        System.out.println(a & b); // * 2
+        System.out.println(a | b); // * 10
+        System.out.println(a ^ b); // * 8
+
+        // ! 5. Assignment operators
+        int c = 10;
+        c += 5; // * c is now 15
+        c -= 5; // * c is now 10
+        c *= 5; // * c is now 50
+        c /= 5; // * c is now 10
+        System.out.println(c);
+    }
+}

HelloWorld.class

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+import java.util.*;
+
+public class Taking_Input {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in); // ? Make the object of the Scanner class to use the method of the Scanner
+        // ? System.in - Is use to get the input read data from the key-board
+
+        // ? Get two number from the user and perform the Arithmetic operation on it
+        System.out.print("Enter Number One : ");
+        int num1 = sc.nextInt();
+        System.out.print("Enter Number Two : ");
+        int num2 = sc.nextInt();
+
+        // ? Output the result to the user
+        System.out.println("The Addition of " + num1 + " + " + num2 + " = " + (num1 + num2));
+        System.out.println("The Subtraction of " + num1 + " - " + num2 + " = " + (num1 - num2));
+        System.out.println("The Multiplication of " + num1 + " * " + num2 + " = " + (num1 * num2));
+        System.out.println("The Division of " + num1 + " / " + num2 + " = " + (num1 / num2));
+
+        sc.close();
+    }
+}