Wednesday, October 12, 2016

Java Programs asked in Interviews

// Java program to Convert String into reverse  String 

public static void main(String[] args) {

String a = "This is my country , And I love my Country";
String b="";
for (int i = a.length()-1; i > 0; i--) {

b+=a.charAt(i);
}
System.out.println(b +"\n" +a);
}
*********************************************************************************
// Java program to reverse integer array 

public static void main(String[] args) {
int[] inputArray = { 2, 4, 6, 3, 8, 9, 44, 3 ,22};
int [] OutputArray = new int [inputArray .length];  // define lenght of int array
int j =0;  // define counter for OutputArray 
// take element from end of  inputArray and add in front of outputArray
for (int i =a.length-1; i>0;i-- ){
b[j]= a[i];

System.out.println(a[i]+"**"+b[j]);
j++; // Increase a counter 
}


}
*********************************************************************************
// Java program to reverse integer array with binary 

*********************************************************************************

//// Java program to reverse words of String 
// input =>"This is my country And I love my Country";
//output => "sihT si ym yrtnuoc dnA I evol ym yrtnuoC"

 public static void main(String[] args) {
String inputString = "This is my country And I love my Country";  //input string

String[] words = inputString.split(" "); //split words, now -->This , is , my , country,..etc

String reverseString = ""; // get output in this.

 // first loop to get get each words one by one from string 
for (int i = 0; i < words.length; i++) {
String word = words[i]; //initi, word  contain -"This" in next iteration it's "is " & so on

String reverseWord = ""; // get a output (reverse word)

//second loop is for to reverse a word
for (int j = word.length() - 1; j >= 0; j--) {
reverseWord = reverseWord + word.charAt(j); //append chars in reverse manner
}

reverseString = reverseString + reverseWord + " "; //appends words as process from inner loop
}

System.out.println(inputString);

System.out.println(reverseString);

}

*********************************************************************************
// Prefix and post fix 

 public static void main(String[] args){
int x;
int a = 100;
System.out.println(a-- +"==="+--a);
                                          //100   99           98
                          //         values   postfix    ,prefix 99 is became 98
x=a-- - --a;
System.out.println(x); //output is -->2
}

}

*********************************************************************************

//To Find Duplicate Elements In An Array 

 public static void main(String[] args)
    {
        String[] strArray = {"abc", "def", "mno", "xyz", "pqr", "xyz", "def"};
        for (int i = 0; i < strArray.length-1; i++) //to take 1 element from array
        {
            for (int j = i+1; j < strArray.length; j++)//compare all the element in array one by one
            {
                if( (strArray[i].equals(strArray[j])) && (i != j) )
//to avoid outOfIndex Error
                {
                    System.out.println("Duplicate Element is : "+strArray[j]);
                }
            }
        }
    }   

*********************************************************************************
// Find Second Largest Number In An Integer Array :

public static void main(String[] args) {

        int firstLargest, secondLargest;
       if(input[0] > input[1])  //Checking first two elements of input array

        {
            //If first element is greater than second element
            firstLargest = input[0];
            secondLargest = input[1];
        }
        else
        {
            //If second element is greater than first element
            firstLargest = input[1];
            secondLargest = input[0];
        }
        //Checking remaining elements of input array
        for (int i = 2; i < input.length; i++)
        {
            if(input[i] > firstLargest)
            {
                //If element at 'i' is greater than 'firstLargest'
                secondLargest = firstLargest;
                firstLargest = input[i];
            }
            else if (input[i] < firstLargest && input[i] > secondLargest)
            {
                //If element at 'i' is smaller than 'firstLargest' and greater than 'secondLargest'
                secondLargest = input[i];
            }
        }

System.out.println(secondLargest );

     }


*********************************************************************************
// Sorting the integer array 


public static void main(String[] args) {
int[] inputArray = { 1, 2, 4, 6, 3, 8, 9, 44, 3, 22 };
        int temp, pos;
        for (int i = 0; i < inputArray.length - 1; i++) //loop for taking first element 
        {
            pos = i;  // initializing pos variable within for loop so every-time it is incremented
            //finding the position of smallest element between (i+1)th element and last element
            for (int j = i+1; j < inputArray.length; j++)
            {
                if(inputArray[j] < inputArray[pos] ) // condition to find smallest element 
                {
                    pos = j;
                }
            }
            //Swapping inputArray[i] and inputArray[pos]
            temp = inputArray[i];
            inputArray[i] = inputArray[pos];
            inputArray[pos] = temp;
        }
        for (int i = 0; i < inputArray.length; i++)
        {
            System.out.print(inputArray[i] + " ");
        }
        System.out.println();
    }
*********************************************************************************
// Find a continues sub array whose sum is equal to inputNumber

public static void main(String[] args) {
int[] inputArray = { 1, 2, 4, 6, 3, 8, 9, 44, 3, 22 };
int inputNumber = 15;
int sum = 0; // Initializing 'sum' to 0


// Iterating through 'inputArray'

for (int i = 0; i < inputArray.length; i++) {
sum = inputArray[i];  // Assigning inputArray[i] to 'sum'


for (int j = i + 1; j < inputArray.length; j++) {
// Adding inputArray[j] to 'sum'

sum = sum + inputArray[j];

// If 'sum' is equal to 'inputNumber' then printing the sub array

if (sum == inputNumber) {
System.out.println("Continuous sub array of "
+ Arrays.toString(inputArray) + " whose sum is "
+ inputNumber + " is ");

                  //print sub array from i element to j element which satisfy a condition 
for (int k = i; k <= j; k++) {
System.out.print(inputArray[k] + " ");
}

System.out.println();
}

// if 'sum' is smaller than 'inputNumber', continue the loop

else if (sum < inputNumber) {
continue;
}

// if 'sum' is greater than 'inputNumber', then break the loop

else if (sum > inputNumber) {
break;
}
}
}

*********************************************************************************
// Reverse The String With Preserving The Position Of Spaces :

public static void main(String[] args) {

String inputString = "Hi this is good tested Nagard";

         
        char[] inputStringArray = inputString.toCharArray();//Converting inputString to char array 'inputStringArray'
         
        //Defining a new char array 'resultArray' with same size as inputStringArray
         
        char[] resultArray = new char[inputStringArray.length];
         
        //First for loop :
        //For every space in the 'inputStringArray',
        //we insert spaces in the 'resultArray' at the corresponding positions
         
        for (int i = 0; i < inputStringArray.length; i++)
        {
            if (inputStringArray[i] == ' ')
            {
                resultArray[i] = ' ';
            }
        }
         
        //Initializing 'j' with length of resultArray
         
        int j = 0;
                 
        //Second for loop :
        //we copy every non-space character of inputStringArray
        //from first to last at 'j' position of resultArray
         
        for (int i = inputStringArray.length-1; i >0; i--)
        {
            if (inputStringArray[i] != ' ')
            {
                //If resultArray already has space at index j then decrementing 'j'
                 
                if(resultArray[j] != ' ')
                {
                   resultArray[j] = inputStringArray[i];
                }
                 
                               
                j++;
            }
        }
         
*********************************************************************************
//Find The Percentage Of Uppercase Letters, Lowercase Letters, Digits And Other Special Characters In A String

 public static void main(String[] args) {


String inputString = "Hi My email id is Test@gmail.com 112 time appear";

 //Getting total no of characters in the given string
         
        int totalChars = inputString.length();
         
        //Initializing upperCaseLetters, lowerCaseLetters, digits and others with 0
         
        int upperCaseLetters = 0;
         
        int lowerCaseLetters = 0;
         
        int digits = 0;
         
        int others = 0;
         
        //Iterating through each character of inputString
         
        for (int i = 0; i < inputString.length(); i++)
        {
            char ch = inputString.charAt(i);
             
            //If ch is in uppercase, then incrementing upperCaseLetters
             
            if(Character.isUpperCase(ch))
            {
                upperCaseLetters++;
            }
             
            //If ch is in lowercase, then incrementing lowerCaseLetters
             
            else if(Character.isLowerCase(ch))
            {
                lowerCaseLetters++;
            }
             
            //If ch is a digit, then incrementing digits
             
            else if (Character.isDigit(ch))
            {
                digits++;
            }
             
            //If ch is a special character then incrementing others
             
            else
            {
                others++;
            }
        }
         
        //Calculating percentage of uppercase letters, lowercase letters, digits and other characters
         
        double upperCaseLetterPercentage = (upperCaseLetters * 100.0) / totalChars ;
         
        double lowerCaseLetterPercentage = (lowerCaseLetters * 100.0) / totalChars;
         
        double digitsPercentage = (digits * 100.0) / totalChars;
         
        double otherCharPercentage = (others * 100.0) / totalChars;
         
        DecimalFormat formatter = new DecimalFormat("##.##");
         
        //Printing percentage of uppercase letters, lowercase letters, digits and other characters
         
        System.out.println("In '"+inputString+"' : ");
         
        System.out.println("Uppercase letters are "+formatter.format(upperCaseLetterPercentage)+"% ");
         
        System.out.println("Lowercase letters are "+formatter.format(lowerCaseLetterPercentage)+"%");
         
        System.out.println("Digits Are "+formatter.format(digitsPercentage)+"%");
         
        System.out.println("Other Characters Are "+formatter.format(otherCharPercentage)+"%");
         
 }
}
***********************************************************************************
// Creation Of Matrix In Java

Scanner sc = new Scanner(System.in);
         
        System.out.println("Enter The Number Of Rows");
         
        int row = sc.nextInt();
         
        System.out.println("Enter The Number Of Columns");
         
        int cols = sc.nextInt();
         
        //defining 2D array to hold matrix data
         
        int[][] matrix = new int[row][cols];
         
        System.out.println("Enter Matrix Data");
         
        for (int i = 0; i < row; i++)
        {
            for (int j = 0; j < cols; j++)
            {
                matrix[i][j] = sc.nextInt();
            }
        }
         
        System.out.println("Your Matrix is : ");
         
        for (int i = 0; i < row; i++)
        {
            for (int j = 0; j < cols; j++)
            {
                System.out.print(matrix[i][j]+"\t");
            }
             
            System.out.println();
        }
  
*********************************************************************************
//Matrix Addition In Java
    
public static void main(String[] args) {


       Scanner sc = new Scanner(System.in); // Make ready compiler to ready from data 
     
       System.out.println("Enter The Number Of Rows");
     
       int row = sc.nextInt();
     
       System.out.println("Enter The Number Of Columns");
     
       int cols = sc.nextInt();
     
       int[][] matrix1 = new int[row][cols]; // Define matrix
     
       int[][] matrix2 = new int[row][cols];
     
       int[][] sum = new int[row][cols];
     
       System.out.println("Enter The Data For First Matrix :");
     
       for (int i = 0; i < row; i++)
       {
           for (int j = 0; j < cols; j++)
           {
               matrix1[i][j] = sc.nextInt();
           }
       }
     
       System.out.println("Enter The Data For Second Matrix :");
     
       for (int i = 0; i < row; i++)
       {
           for (int j = 0; j < cols; j++)
           {
               matrix2[i][j] = sc.nextInt();
           }
       }
     
     
       System.out.println("Sum = ");
     
       for (int i = 0; i < row; i++)
       {
           for (int j = 0; j < cols; j++)
           {
               sum[i][j] = matrix1[i][j] + matrix2[i][j];
             
               System.out.print(sum[i][j]+"\t");
           }
         
           System.out.println();
       }
*********************************************************************************
// Multiplication of Matrix 
 public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
         
        System.out.println("Enter The Number Of Rows In First Matrix");
         
        int rowsInFirst = sc.nextInt();
         
        System.out.println("Enter The Number Of Columns In First Matrix / Rows In Second Matrix");
         
        int colsInFirstRowsInSecond = sc.nextInt();
         
        System.out.println("Enter The Number Of Columns In Second Matrix");
         
        int colsInSecond = sc.nextInt();
         
        int[][] matrix1 = new int[rowsInFirst][colsInFirstRowsInSecond];
         
        int[][] matrix2 = new int[colsInFirstRowsInSecond][colsInSecond];
         
        int[][] product = new int[rowsInFirst][colsInSecond];
         
        System.out.println("Enter The Data For First Matrix :");
         
        for (int i = 0; i < rowsInFirst; i++)
        {
            for (int j = 0; j < colsInFirstRowsInSecond; j++)
            {
                matrix1[i][j] = sc.nextInt();
            }
        }
         
        System.out.println("Enter The Data For Second Matrix :");
         
        for (int i = 0; i < colsInFirstRowsInSecond; i++)
        {
            for (int j = 0; j < colsInSecond; j++)
            {
                matrix2[i][j] = sc.nextInt();
            }
        }
         
            
        System.out.println("Product = ");
         
        for (int i = 0; i < rowsInFirst; i++)
        {
            for (int j = 0; j < colsInSecond; j++)
            {
                for (int k = 0; k < colsInFirstRowsInSecond; k++)
                {
                    product[i][j] +=  matrix1[i][k] * matrix2[k][j];
                }
            }
        }
         
        for (int i = 0; i < rowsInFirst; i++)
        {
            for (int j = 0; j < colsInSecond; j++)
            {
                System.out.print(product[i][j]+"\t");
            }
             
            System.out.println();
        }
    }
*********************************************************************************
// Transpose of Matrix (Rows into col and col into rows)
  public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
         
        System.out.println("Enter The Number Of Rows");
         
        int rows = sc.nextInt();
         
        System.out.println("Enter The Number Of Columns");
         
        int cols = sc.nextInt();
         
        int[][] matrix = new int[rows][cols];
     
        int[][] transpose = new int[cols][rows];
         
        System.out.println("Enter The Data For Matrix :");
         
        for (int i = 0; i < rows; i++)
        {
            for (int j = 0; j < cols; j++)
            {
                matrix[i][j] = sc.nextInt();
            }
        }
         

        System.out.println("Transpose of Matrix is :");
         
        for (int i = 0; i < rows; i++)
        {
            for (int j = 0; j < cols; j++)
            {
                transpose[j][i] = matrix[i][j]; // Just need to change position of i and j
            }
        }
         
        for (int i = 0; i < cols; i++)
        {
            for (int j = 0; j < rows; j++)
            {
                System.out.print(transpose[i][j]+"\t");
            }
             
            System.out.println();
        }

 ********************************************************************************
//To Reverse And Add A Number Until You Get A Palindrome (number whose reverse ==  original number  . ie 123321 ):

Posted by at 8 comments:
Subscribe to: Comments (Atom)