Nested while loop in java

Nested while loop:

• Defining a while loop inside another loop.
• Inner loop executes only if outer loop conditions satisfies.
• Loop terminates only if outer loop condition fails.

Analyze the code:

class Test 
{
	public static void main(String[] args) 
	{
		int i=1;
		while(i<=5)
		{
			System.out.print("i : " + i + "\t ---> ");
			
			int j=1;
			while(j<=5)
			{
				System.out.print("j : " + j + "\t");
				++j;
			}
			System.out.println();

			++i;
		}
	}
}

• We can process two dimensional data using nested loops easily.
• Outer loop represents number of rows
• Inner loop represents number of columns.
• Nested loops are used to process Multi dimensional arrays and Printing Patterns.

Simple pattern printing:

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

class Test 
{
	public static void main(String[] args) 
	{
		int i=1;
		while(i<=5)
		{
			int j=1;
			while(j<=5)
			{
				System.out.print("* ");
				++j;
			}
			System.out.println();
			++i;
		}
	}
}

Pattern printing:

1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5

class Test 
{
	public static void main(String[] args) 
	{
		int i=1;
		while(i<=5)
		{
			int j=1;
			while(j<=5)
			{
				System.out.print(j + " ");
				++j;
			}
			System.out.println();

			++i;
		}
	}
}

Printing Combinations:

class Test 
{
	public static void main(String[] args) 
	{
		int i=1;
		while(i<=5)
		{
			int j=1;
			while(j<=5)
			{
				System.out.print("(" + i  + " , " + j + ")  ");
				++j;
			}
			System.out.println();
			++i;
		}
	}
}

Output:

(1 , 1)  (1 , 2)  (1 , 3)  (1 , 4)  (1 , 5)
(2 , 1)  (2 , 2)  (2 , 3)  (2 , 4)  (2 , 5)
(3 , 1)  (3 , 2)  (3 , 3)  (3 , 4)  (3 , 5)
(4 , 1)  (4 , 2)  (4 , 3)  (4 , 4)  (4 , 5)
(5 , 1)  (5 , 2)  (5 , 3)  (5 , 4)  (5 , 5)

class Loops
{
	public static void main(String[] args) 
	{
		int i=0;
		while(++i<=5)
		{
			int j=0;
			while(++j<=5)
			{
				System.out.println("(i , j ) : "+i+","+j);
			}
		}
	}
}

Output the code:

class Loops
{
	public static void main(String[] args) 
	{
		int i=0, j=0;
		while(++i<=5)
		{
			while(++j<=5)
			{
				System.out.println("J value : "+j);
			}
			System.out.println("J value : "+j);
		}
	}
}

Output it:

class Loops
{
	public static void main(String[] args) 
	{
		int i=1, j=1;
		while(i++ <= 4)
		{
			while(j++ <= 3)
			{
			}
		}
		System.out.println("final i value : "+i);
		System.out.println("final j value : "+j);
	}
}