Learn Java Part 11

Java ppt11 from Gurpreet singh

Get Current Date in java

To get current date in java write following code:

            DateFormat dateFormat=new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
            Date date=new Date(); //get current date and time
            System.out.println(""+dateFormat.format(date));


Import statements:

import java.text.*;

for each loop in java

What is for each loop?
for each loop in java is the enhanced version of for loop. It is introduced from JDK 5. It is used to iterate all elements of an array or Collection.

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Syntax:

for ( data-type variableName :  array or collection )
{
    //statements
}

---

Consider the following program:

public class ForEachLoop
{
    public static void main(String[] args)
    {
        int[] array ={ 1, 2, 3, 4, 5 };
        System.out.println("Array elements: ");

        for(int element: array)
               System.out.print(element+"  ");

    }
}

Write the above program in Notepad and save it as ForEachLoop.java 
Compile and run it to get the following output:

Array elements: 
1  2  3  4  5

the loop for(int element: array)
fetches the elements of array and assign it to variable element so we can use element to access the elements of array

Consider the following program to access elements of multi-dimensional array

public class ForEachLoop
{
    public static void main(String[] args)
    {
     int[][] array ={ {1, 2, 3, 4,},{ 5,6,7,8} }; //array with 2 rows and 4 columns
        System.out.println("Array elements: ");
        for(int[] row: array)
            for(int element: row)
               System.out.print(element+"  ");
    }
}

Write the above program in Notepad and save it as ForEachLoop.java 
Compile and run it to get the following output:

Array elements: 
1  2  3  4  5  6  7  8

the loop for(int[ ] row: array)
fetches one row of array and assign it to variable row so we can use row to access one row(or one dimensional array) of array

the loop for(int element: row)
fetches the elements of row and assign it to variable element so we can use element to access the elements of row

Command Line Arguments

public class CommandLineArguments
{
    public static void main(String[] args)
    {
        System.out.println("Total number of Command Line Arguments: "+args.length);
        System.out.println("Command Line Arguments:");
        for(int i=0;i<args.length;i++)
            System.out.println(args[i]);
    }
}

Type the above program in Notepad and Save it as CommandLineArguments.java
Compile like this:

javac  CommandLineArguments.java

Run like this:

java  CommandLineArguments   Arguments

For example: 

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java  CommandLineArguments   Hello World
output:

Total number of Command Line Arguments: 2
Command Line Arguments:
Hello
World

---

If you run like this:
java  CommandLineArguments
output:

Total number of Command Line Arguments: 0
Command Line Arguments:

---

Note: Each argument in command line arguments is seperated by a space

Learn Java Part 10

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Learn Java Part 10 from Gurpreet singh

Learn Java Part 9

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Learn Java Part 9 from Gurpreet singh

Learn Java Part 8

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Learn Java Part 8 from Gurpreet singh

Program to reverse each word of a given string

//Program to reverse each word of a given string

import java.io.*;  //for IOException, BufferedReader, InputStreamReader
import java.util.*;  //for StringBuffer
public class WordReverse {
    public static void main(String[] args)throws IOException
    {
    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
    System.out.println("Enter the string:");
    String str=br.readLine();
    StringTokenizer st=new StringTokenizer(str);
    String temp="";
    while(st.hasMoreTokens())
    {
        temp=temp+new StringBuffer(st.nextToken()).reverse().toString()+" ";
    }
        System.out.println("Reversed String is:");
        System.out.println(temp);
    }   
}

Output:

Enter the string:
Hello this is GsbProgramming
Reversed String is:
olleH siht si gnimmargorPbsG 

Program to calculate how many times a word occurs in a given string in just one line

//Program to calculate how many times a word occurs in a given string in just one line

import java.io.*;  //for IOException, BufferedReader, InputStreamReader
class CountWord
{
  public static void main(String args[]) throws IOException
  {
     System.out.println("Enter the string: ");
     BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
     String s=br.readLine();  //Gets a string from user
     System.out.println("Enter the word to search for: ");
     String word=br.readLine();  //Gets a string from user

     int count=(s.length()-s.replace(word+"", "").length())/word.length();     

   System.out.println(word+" occurs in given string for: "+count+" times");
  }
}

How to get an alert when anyone logs into your Facebook account from a new device or browser?

Follow these steps:

• Log In into your Facebook account and goto Settings.

• Then Jump to “Security Settings” Tab and You can see a Login “Login Alerts” and Click on “Edit”.

• Check the Get notifications

• If you want to receive emails alerts then check it

• If you want to receive text messages alerts then check it

• Click Save Changes and enter your current password and click Submit

• Your changes will be saved and now will get an alert when anyone logs into your Facebook account from a new device or browser