In the previous tutorial of Java Interview Questions and Answers Part 1, I have explained some basic coding problems of Java.This part is in continuation with the previous Java Interview Questions and Answers tutorial. In this part of the tutorial we are proceeding with more problems based on further concepts of Java and trying to guide you with the best possible explanations.

11- Calculate Circle Area using radius

/* This program shows how to calculate area of circle using it's radius.*/

    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    public class CalculateCircleAreaExample {
    public static void main(String[] args) {
    int radius = 0;
    System.out.println("Please enter radius of a circle");
    try
    {
    //get the radius from console
    BufferedReader br = new BufferedReader(new
    InputStreamReader(System.in));
    radius = Integer.parseInt(br.readLine());
    }
    //if invalid value was entered
    catch(NumberFormatException ne)
    {
    System.out.println("Invalid radius value" + ne);
    System.exit(0);
    }
    catch(IOException ioe)
    {
    System.out.println("IO Error :" + ioe);
    System.exit(0);
    }
    /*
    * Area of a circle is
    * pi * r * r
    * where r is a radius of a circle.
    */
    //NOTE : use Math.PI constant to get value of pi
    double area = Math.PI * radius * radius;
    }
    System.out.println("Area of a circle is " + area);
    }

Output of Calculate Circle Area using Java Example would be

/*
Please enter radius of a circle
19
Area of a circle is 1134.1149479459152
*/

12 - Factorial of a number using recursion

/* This program shows how to calculate

Factorial of a number using recursion function. */

    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    public class JavaFactorialUsingRecursion {
    public static void main(String args[]) throws NumberFormatException,
    IOException{
    System.out.println("Enter the number: ");
    //get input from the user
    BufferedReader br=new BufferedReader(new
    InputStreamReader(System.in));
    int a = Integer.parseInt(br.readLine());
    //call the recursive function to generate factorial
    int result= fact(a);
    }
    System.out.println("Factorial of the number is: " + result);
    static int fact(int b)
    {
    if(b <= 1)
    //if the number is 1 then return 1
    return 1;
    else
    //else call the same function with the value - 1
    return b * fact(b-1);
    }
    }

Output of this Java example would be

/*
Enter the number:
5
Factorial of the number is: 120
*/

13 pyramid of numbers using for loops

/* Generate Pyramid For a Given Number Example

This Java example shows how to generate a pyramid of numbers for given number using for loop example. */

    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    public class GeneratePyramidExample {
    public static void main (String[] args) throws Exception{
    BufferedReader keyboard = new BufferedReader (new
    InputStreamReader(System.in));
    System.out.println("Enter Number:");
    int as= Integer.parseInt (keyboard.readLine());
    System.out.println("Enter X:");
    int x=
    Integer.parseInt (keyboard.readLine());
    int y = 0;
    for(int i=0; i<= as ;i++){
    for(int j=1; j <= i ; j++){
    System.out.print(y + "\t");
    y = y + x;
    }
    System.out.println("");
    }
    }
    }

Output of this Java example would be

/*
Enter Number:
5
Enter X:
1
0
1 2 3 4 5 6 7 8 9
12 13
10 11
14
----------------------------------------------
Enter Number:
5
Enter X:
2
0
2 4
6 8
10
12 14 16 18
20 22 24 26
28
----------------------------------------------
Enter Number:
5
Enter X:
3
0
3 6 9 12 15 18 21 24 27
30 33 36 39
42

*/

14 To Find Maximum of Two Numbers.

/* To Find Maximum of 2 Numbers using if else */

    class Maxoftwo{
    public static void main(String args[]){
    //taking value as command line argument.
    //Converting String format to Integer value
    int i = Integer.parseInt(args[0]);
    int j = Integer.parseInt(args[1]);
    if(i > j)
    System.out.println(i+" is greater than "+j);
    else
    System.out.println(j+" is greater than "+i);
    }
    }

Output of this Java example would be

/*
i=10 , j=15
15 is greater than 10
*/

15 To Find Minimum of Two Numbers using conditional operator.

/* To find minimum of 2 Numbers using ternary operator */

class Minoftwo{
public static void main(String args[]){
//taking value as command line argument.
//Converting String format to Integer value
int i = Integer.parseInt(args[0]);
int j = Integer.parseInt(args[1]);
int result = (i<j)?i:j ;
System.out.println(result+" is a minimum value");
}
}

Output of this Java example would be

/*
i=10,j=15
Output would be
10 is a minimum value"
*/

16-Write a program that will read a float type value from the print the following output.

->Small Integer not less than the number.

->Given Number.

->Largest Integer not greater than the number. */

    class ValueFormat{
    public static void main(String args[]){
    double i = 34.32; //given number
    System.out.println("Small Integer not greater than the number :
    "+Math.ceil(i));
    System.out.println("Given Number : "+i);
    System.out.println("Largest Integer not greater than the number :
    "+Math.floor(i));
    }

Output of this Java example would be

Small Integer not greater than the number :35.0                                                                                                                  
Given Number : 34.32                                                                                                                                             
Largest Integer not greater than the number :34.0 

17 - Write a program to generate 5 Random nos. between 1 to 100, and it should not follow with decimal point.

    class RandomDemo{
    public static void main(String args[]){
    for(int i=1;i<=5;i++){
    System.out.println((int)(Math.random()*100));
    }
    }
    }

Output of this Java example would be

/*
79                                                                                                                                                               
97                                                                                                                                                               
27                                                                                                                                                               
94                                                                                                                                                               
22 */

18 - Write a program to display a greet message according to Marks obtained by student.

    class SwitchDemo{
    public static void main(String args[]){
    int marks = Integer.parseInt(args[0]);
    as command line argument.
    switch(marks/10){
    case 10:
    case 9:
    case 8:
    System.out.println("Excellent");
    break;
    case 7:
    System.out.println("Very Good");
    break;
    case 6:
    System.out.println("Good");
    break;
    case 5:
    System.out.println("Work Hard");
    break;
    case 4:
    System.out.println("Poor");
    break;
    case 3:
    //take markscase 2:
    case 1:
    case 0:
    System.out.println("Very Poor");
    break;
    default:
    System.out.println("Invalid value Entered");
    }
    }
    }

Output of this Java example would be

/*marks=89
Excellent*/

19 - Write a program to find SUM AND PRODUCT of a given Digit.

class Sum_Product_ofDigit{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
//taking value as command line argument.
int temp = num,result=0;
//Logic for sum of digit
while(temp>0){
result = result + temp;
temp--;
}
System.out.println("Sum of Digit for "+num+" is : "+result);
//Logic for product of digit
temp = num;
result = 1;
while(temp > 0){
result = result * temp;
temp--;
}
System.out.println("Product of Digit for "+num+" is : "+result);
}
}

Output of this Java example would be

/*
num=345

Sum of Digit for 345 is : 12
Product of Digit for 345 is : 60
*/

20 - Write a program to find sum of all integers greater than 100 and less than 200 that are divisible by 7.

    class SumOfDigit{
    public static void main(String args[]){
    int result=0;
    for(int i=100;i<=200;i++){
    if(i%7==0)
    result+=i;
    }
    System.out.println("Output of Program is : "+result);
    }
    }

Output of this Java example would be

Output of Program is : 2107   

In the next session , we will continue with other important Java coding questions asked by Interviewer.