Saturday, 31 October 2015

Basic Interview Questions

Multiplication of two matrixes


import java.util.Scanner;
class Multiplication
{
void doMultiply(int arr1[][],int arr2[][])
{
int arr3[][]=new int[3][3];
for(int i=0;i<arr1.length;i++)
{
for(int j=0;j<arr2[0].length;j++)
{
arr3[i][j]=0;
for(int k=0;k<arr1[0].length;k++)
{
arr3[i][j]=arr3[i][j]+arr1[i][k]*arr2[k][j];
}
}
}
for(int i=0;i<arr3.length;i++)
{
for(int j=0;j<arr3[i].length;j++)
{
System.out.print(arr3[i][j]+"\t");
}
System.out.println();
}
}
}
class MultiplicationTest
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
int arr1[][]=new int[3][3];
int arr2[][]=new int[3][3];
System.out.println("Enter the elements of first matrix:");
for(int i=0;i<arr1.length;i++)
{
for(int j=0;j<arr1[i].length;j++)
{
arr1[i][j]=sc.nextInt();
}
}
System.out.println("Enter the elements of second matrix:");
for(int i=0;i<arr2.length;i++)
{
for(int j=0;j<arr2[i].length;j++)
{
arr2[i][j]=sc.nextInt();
}
}
Multiplication m1=new Multiplication();
m1.doMultiply(arr1,arr2);
}
}

Merging two sorted arrays


import java.util.Scanner;
class Merge
{
void toMerge(int arr1[],int arr2[])
{
int arr3[]=new int[arr1.length+arr2.length];
int i=0,j=0,k=0;
while(i<arr1.length&&j<arr2.length)
{
if(arr1[i]<arr2[j])
{
arr3[k]=arr1[i];
k++;
i++;
}
else
{
arr3[k]=arr2[j];
k++;
j++;
}
}
for(int m=j;m<arr2.length;m++,k++)
arr3[k]=arr2[m];
for(int m=i;m<arr1.length;m++,k++)
arr3[k]=arr1[m];
for(int t=0;t<k;t++)
System.out.print(arr3[t]+"\t");
}
}
class MergeTest
{
public static void main(String args[])
{
Merge m1=new Merge();
Scanner sc=new Scanner(System.in);
System.out.println("Enter the value of n:");
int n=sc.nextInt();
System.out.println("Enter the value of m:");
int m=sc.nextInt();
int arr1[]=new int[n];
int arr2[]=new int[m];
System.out.println("Enter the elements of first array in sorted order:");
for(int i=0;i<n;i++)
arr1[i]=sc.nextInt();
System.out.println("Enter the elements of second array in sorted order:");
for(int i=0;i<m;i++)
arr2[i]=sc.nextInt();
m1.toMerge(arr1,arr2);
}
}

Reversing an array(shortest method)

import java.util.Scanner;
class ReverseArray
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
int arr[]=new int[n];
for(int i=0;i<n;i++)
arr[i]=sc.nextInt();
System.out.println("array is:");
for(int i=0;i<n;i++)
System.out.print(arr[i]+"\t");
for(int i=0;i<n/2;i++)
{
int temp=arr[i];
arr[i]=arr[arr.length-1-i];
arr[arr.length-i-1]=temp;
}
System.out.println("reverse array is:");
for(int i=0;i<n;i++)
System.out.print(arr[i]+"\t");
}
}

Removing Duplicates From Array

import java.util.Scanner;
class Duplicate
{
void removeDuplicate(int arr[])
{
int size=arr.length;
for(int i=0;i<size-1;i++)
{
for(int j=i+1;j<size;j++)
{
if(arr[i]==arr[j])
{
while(j<size-1)
{
arr[j]=arr[j+1];
j++;
}
size--;
}
}
}
for(int i=0;i<size;i++)
System.out.println(arr[i]);
}
}
class DuplicateTest
{
public static void main(String args[])
{
Duplicate d1=new Duplicate();
Scanner sc=new Scanner(System.in);
System.out.println("enter the values of n:");
int n=sc.nextInt();
int arr[]=new int[n];
for(int i=0;i<n;i++)
{
arr[i]=sc.nextInt();
}
d1.removeDuplicate(arr);
}
}

Perfect Number

import java.util.Scanner;
class Perfect
{
void findPerfect(int n)
{
int temp=n;
int sum=0;
for(int i=1;i<=n/2;i++)
{
if(n%i==0)
sum=sum+i;
}
if(temp==sum)
System.out.println("Perfect");
else
System.out.println("Not a Perfect");
}
}
class PerfectTest
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
Perfect d1=new Perfect();
int number=sc.nextInt();
d1.findPerfect(number);
}
}

Armstrong Number

import java.util.Scanner;
class Armstrong
{
void findArmstromg(int n)
{
int temp=n;
int r=0;
int sum=0;
while(n>0)
{
r=n%10;
sum=sum+r*r*r;
n=n/10;
}
if(temp==sum)
System.out.println("Armstrong");
else
System.out.println("Not a Armstrong");
}
}
class ArmstrongTest
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
Armstrong d1=new Armstrong();
int number=sc.nextInt();
d1.findArmstromg(number);
}
}

swapping two numbers without using third variable

import java.util.Scanner;
class Swap
{
void swap1(int a,int b)
{
a=a+b;
b=a-b;
a=a-b;
System.out.println("value of a is:"+a);
System.out.println("value of b is:"+b);
}
void swap2(int a,int b)
{
a=a^b;
b=a^b;
a=a^b;
System.out.println("value of a is:"+a);
System.out.println("value of b is:"+b);
}
void swap4(int a,int b)
{
a=a+b-(b=a);
System.out.println("value of a is:"+a);
System.out.println("value of b is:"+b);
}
void swap5(int a,int b)
{
a=b-~a-1;
b=a+~b+1;
a=a+~b+1;
System.out.println("value of a is:"+a);
System.out.println("value of b is:"+b);
}

}
class SwapTest
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
int a=sc.nextInt();
int b=sc.nextInt();
Swap s1=new Swap();
System.out.println("value of a is:"+a);
System.out.println("value of b is:"+b);
s1.swap1(a,b);
s1.swap2(a,b);
s1.swap5(a,b);
s1.swap4(a,b);
}
}

Reverse of a number

import java.util.Scanner;
class Reverse
{
void printReverse(int number)
{
int r=0;
int reverse=0;
while(number>0)
{
r=number%10;
reverse=reverse*10+r;
number=number/10;
}
System.out.println(reverse);
}
}
class ReverseTest
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
int number=sc.nextInt();
Reverse m1=new Reverse();
m1.printReverse(number);
}
}

Greatest of three numbers

import java.util.Scanner;
class Maximum
{
void printMaximum(int a,int b,int c)
{
int max=a;
if(b>max)
max=b;
if(c>max)
max=c;
System.out.printf("maximum is %d",max);
}
}
class MaximumTest
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
int a=sc.nextInt();
int b=sc.nextInt();
int c=sc.nextInt();
Maximum m1=new Maximum();
m1.printMaximum(a,b,c);
}
}

Factorial(with or without recursion)

import java.util.Scanner;
class Factorial
{
void printFactorial(int number)
{
int fact=1;
for(int i=1;i<=number;i++)
fact=fact*i;
System.out.println(fact);
}
int printFactorialRecursion(int number)
{
if(number==0)
return 1;
else
return number*printFactorialRecursion(number-1);
}
}
class FactorialTest
{
public static void main(String args[])
{
Factorial f1=new Factorial();
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
f1.printFactorial(n);
int t=f1.printFactorialRecursion(n);
System.out.println(t);
}
}

Fibonacci series

import java.util.Scanner;
class Fibonacci
{
//this will find  Fibonacci upto the maximum number given
void printSeries(int number)
{
int sum=0;
int a=1;
int b=1;
System.out.printf("%d%d",a,b);
while(sum<number)
{
sum=a+b;
System.out.print(sum);
b=a;
a=sum;
}
}
//this will find Fibonacci upto n terms
int fibrecursion(int number)
{
if(number==0||number==1)
return 1;
else
return fibrecursion(number-1)+fibrecursion(number-2);
}
}
class FibonacciTest
{
public static void main(String args[])
{
Fibonacci f1=new Fibonacci();
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
//f1.printSeries(n);
for(int i=0;i<n;i++)
{
int t=f1.fibrecursion(i);
System.out.println(t);
}
}
}

Find gcd of two numbers

import java.util.Scanner;
class Gcd
{
void toFindGcd(int number1,int number2)
{
while(number1!=number2)
{
if(number1>number2)
number1=number1-number2;
else
number2=number2-number1;
}
System.out.printf("gcd of these two numbers is: %d",number1);
}
}
class GcdTest
{
public static void main(String args[])
{
Gcd g1=new Gcd();
Scanner sc=new Scanner(System.in);
int n1=sc.nextInt();
int n2=sc.nextInt();
g1.toFindGcd(n1,n2);
}
}

Check whether a given string is palindrome or not

//It can be done by three methods.
import java.util.Scanner;
class Palindrome
{
private boolean found=true;
void palByLogic(String s1)
{
char a[]=new char[s1.length()];
a=s1.toCharArray();
for(int i=0;i<s1.length()/2;i++)
{
if(a[i]!=a[s1.length()-i-1])
{
found=false;
break;
}
}
if(found==false)
System.out.println("not a palindrome:");
else
System.out.println("palindrome:");
}
void palByStBuffer(String s1)
{
StringBuffer s2=new StringBuffer(s1);
String s3=s2.reverse().toString();
if(s1.equals(s3))
System.out.println("Palindrome:");
else
System.out.println("Not a Palindrome:");
}
void palByStBuiler(String s1)
{
StringBuilder s2=new StringBuilder(s1);
String s3=s2.reverse().toString();
if(s1.equals(s3))
System.out.println("Palindrome:");
else
System.out.println("Not a Palindrome:");
}
}
class PalindromeTest
{
public static void main(String args[])
{
Palindrome p1=new Palindrome();
Scanner sc=new Scanner(System.in);
System.out.println("Enter the String:");
String s1=sc.next();
p1.palByLogic(s1);
p1.palByStBuffer(s1);
p1.palByStBuiler(s1);
}
}

Find all the prime numbers less than a given number

import java.util.Scanner;
class BeforePrimeNumber
{
void checkBeforePrimeNumber(int number)
{
if(number==2)
System.out.print("2");
else
System.out.print(2+"\t"+3+"\t");
for(int j=4;j<number;j++)
{
boolean found=true;
for(int i=2;i*i<=number;i++)
{
if(j%i==0)
{
found=false;
}
}
if(found==true)
System.out.print(j+"\t");
}
}
}
class BeforePrimeNumberTest
{
public static void main(String args[])
{
BeforePrimeNumber p1=new BeforePrimeNumber();
Scanner sc=new Scanner(System.in);
System.out.println("Enter the number you want to insert:");
int n=sc.nextInt();
p1.checkBeforePrimeNumber(n);
}
}

Check whether a given number is prime or not.

import java.util.Scanner;
class CheckPrime
{
boolean found=true;
void checkCheckPrime(int number)
{
for(int i=2;i*i<number;i++)
{
if(number%i==0)
{
found=false;
break;
}
}
if(found==true)
System.out.println("number is Prime");
else
System.out.println("number is not Prime");
}
}
class CheckPrimeTest
{
public static void main(String args[])
{
CheckPrime p1=new CheckPrime();
Scanner sc=new Scanner(System.in);
System.out.println("Enter the number you want to insert:");
int n=sc.nextInt();
p1.checkCheckPrime(n);
}
}

Monday, 19 October 2015

java quizs

java quiz-3

java quiz-3



1
suppose you have  taken input as x=96 y=96.35 and s=java
what will be the output?
import java.util.Scanner;

public class Solution
{
public static void main(String[] args)
{
            Scanner sc=new Scanner(System.in);
            int x=sc.nextInt();
            double y=sc.nextDouble();
            String s=sc.nextLine();
            System.out.print(x);
            System.out.print(y);
            System.out.print(s);
}
}

9696.35java
96 96.35 java
CompileError
9696.35

2
class Wrap
{
public static void main(String args[])
{
Boolean b1=new Boolean("java");
System.out.println(b1);
}
}
java
false
true
compileError


3
class String_Check
{
public static void main(String args[])
{
String s1=new String();
System.out.print(s1);
}
}
null
no output
String_Check@15db9742
compile error


4
class String_Check
{
public static void main(String args[])
{
String s3=null;
String s4=null;
System.out.println(s3.equals(s4));
}
}
null
true
false
a compile time exception


5
public class B extends A
{
private int bar;
public void setBar(int b)
{
bar = b;
}
}
class A {
public int foo;
}
class A is tightly encapsulated
class B is tightly encapsulated
class A and B is tightly encapsulated
neither class A nor class B is tightly encapsulated


6
class A
{
public void baz()
{
System.out.println("A");
}
}
class B extends A
{
public static void main(String [] args)
{
A a = new B();
a.baz();
}
public void baz() {
System.out.println("B");
}
}
A
B
compilation error
runtime exception


7
class ThreeConst
{
public static void main(String [] args)
{
new ThreeConst(4L);
}
public ThreeConst(int x) {
this();
System.out.print(" " + (x * 2));
}
public ThreeConst(long x) {
this((int) x);
System.out.print(" " + x);
}
public ThreeConst()
{
 System.out.print("no-arg ");
}
}
4
8 4 no-arg
no-arg 8 4
compile time error


8
int x;
x=n.test();
int test()
{
//line x
return y;
}
which line of code,inserted at line x,will not compile?
short y=7;
int y=(int)7.2d;
Byte y=7;
int y=0xface;


9
class Test
{
public static Foo f = new Foo();
 public static Foo f2;
 public static Bar b = new Bar();

 public static void main(String [] args)
 {
 for (int x=0; x<6; x++)
{
 f2 = getFoo(x);
 f2.react();
 }
 }
 static Foo getFoo(int y)
 {
 if ( 0 == y % 2 )
 {
 return f;
 }
else
{
 return b;
 }
 }
 }
 class Bar extends Foo
 {
 void react()
 {
 System.out.print("Bar "); }
 }
 class Foo {
 void react() { System.out.print("Foo "); }

 }
Bar Bar Bar Bar Bar Bar
Foo Bar Foo Bar Foo Bar
Foo Foo Foo Foo Foo Foo.
Compile error.


10
class Foo
{
String doStuff(int x) { return "hello"; }

}
which method would not be legal in a subclass of Foo?
 String doStuff(int  x) { return "hello"; }
 int doStuff(int x) { return 42; }
 public String doStuff(int x) { return "Hello"; }
 protected String doStuff(int x) { return "Hello"; }