Arrays.java

// Graham Mitchell's crappy intro to arrays
// The book is better than this.

public class Arrays
{
	public static void main( String[] args )
	{
		// traditional "native" arrays
		
		// a: [ ][ ][ ][ ][ ][ ][ ][ ][ ][ ]
		//     0  1  2  3  4  5  6  7  8  9
		
		int      x = 10;
		double   y = 5.3;
		String   t = "Bob";
		
		String[] a = new String[10];
		
		a[0] = "VICTORY";	// storing a value
		a[1] = "EPIC FAIL";
		
		String s = a[0];	// retrieving a value
		System.out.println( a[1] );
		
		a[0] = "FLAWLESS VICTORY";	// replacing an existing value






		int[] arr = new int[5];
		int i;
		
		arr[0] = 0;
		arr[1] = 0;
		arr[2] = 0;
		arr[3] = 0;
		arr[4] = 0;
		
		System.out.println("Array contains: " + arr[0] + " " + arr[1] + " " + arr[2] + " " + arr[3] + " " + arr[4] );
		
		// Fill each slot of this array with a random number 1-100
		arr[0] = 1 + (int)(Math.random()*100);
		arr[1] = 1 + (int)(Math.random()*100);
		arr[2] = 1 + (int)(Math.random()*100);
		arr[3] = 1 + (int)(Math.random()*100);
		arr[4] = 1 + (int)(Math.random()*100);

		// Display them again.
		System.out.println("Array contains: " + arr[0] + " " + arr[1] + " " + arr[2] + " " + arr[3] + " " + arr[4] );
		
		// First dumb thing.
		i = 0;
		arr[i] = 1 + (int)(Math.random()*100);
		i = 1;
		arr[i] = 1 + (int)(Math.random()*100);
		i = 2;
		arr[i] = 1 + (int)(Math.random()*100);
		i = 3;
		arr[i] = 1 + (int)(Math.random()*100);
		i = 4;
		arr[i] = 1 + (int)(Math.random()*100);
		
		// Display them again.
		System.out.print("Array contains: ");
		i = 0;
		System.out.print(arr[i] + " ");
		i = 1;
		System.out.print(arr[i] + " ");
		i = 2;
		System.out.print(arr[i] + " ");
		i = 3;
		System.out.print(arr[i] + " ");
		i = 4;
		System.out.print(arr[i] + " ");
		System.out.println();
		

		// Second dumb thing.
		i = 0;
		arr[i] = 1 + (int)(Math.random()*100);
		i = i + 1;
		arr[i] = 1 + (int)(Math.random()*100);
		i = i + 1;
		arr[i] = 1 + (int)(Math.random()*100);
		i = i + 1;
		arr[i] = 1 + (int)(Math.random()*100);
		i = i + 1;
		arr[i] = 1 + (int)(Math.random()*100);
		
		// Display them again.
		System.out.print("Array contains: ");
		i = 0;
		System.out.print(arr[i] + " ");
		i = i + 1;
		System.out.print(arr[i] + " ");
		i = i + 1;
		System.out.print(arr[i] + " ");
		i = i + 1;
		System.out.print(arr[i] + " ");
		i = i + 1;
		System.out.print(arr[i] + " ");
		System.out.println();


		// Third dumb thing.
		i = 0;
		arr[i] = 1 + (int)(Math.random()*100);
		i++;
		arr[i] = 1 + (int)(Math.random()*100);
		i++;
		arr[i] = 1 + (int)(Math.random()*100);
		i++;
		arr[i] = 1 + (int)(Math.random()*100);
		i++;
		arr[i] = 1 + (int)(Math.random()*100);
		
		// Display them again.
		System.out.print("Array contains: ");
		i = 0;
		System.out.print(arr[i] + " ");
		i++;
		System.out.print(arr[i] + " ");
		i++;
		System.out.print(arr[i] + " ");
		i++;
		System.out.print(arr[i] + " ");
		i++;
		System.out.print(arr[i] + " ");
		System.out.println();


		// Less dumb way; use a FRIGGIN' LOOP!
		i = 0;
		while ( i < 5 )
		{
			arr[i] = 1 + (int)(Math.random()*100);
			i++;
		}
		
		// Display them again.
		System.out.print("Array contains: ");
		i = 0;
		while ( i < 5 )
		{
			System.out.print(arr[i] + " ");
			i++;
		}
		System.out.println();


		// Less dumb way #2; use a FRIGGIN' LOOP!
		i = 0;
		while ( i < arr.length )
		{
			arr[i] = 1 + (int)(Math.random()*100);
			i++;
		}
		
		// Display them again.
		System.out.print("Array contains: ");
		i = 0;
		while ( i < arr.length )
		{
			System.out.print(arr[i] + " ");
			i++;
		}
		System.out.println();


		// Awesome way!  "Use the FOR LOOP."
		for ( i=0 ; i < arr.length ; i++ )
		{
			arr[i] = 1 + (int)(Math.random()*100);
		}
		
		// Display them again.
		System.out.print("Array contains: ");
		for ( i=0 ; i < arr.length ; i++ )
		{
			System.out.print(arr[i] + " ");
		}
		System.out.println();


		// Awesome way!  "Use the FOR LOOP."
		for ( i=0 ; i < arr.length ; i++ )
			arr[i] = 1 + (int)(Math.random()*100);
		
		// Display them again.
		System.out.print("Array contains: ");
		for ( i=0 ; i < arr.length ; i++ )
			System.out.print(arr[i] + " ");
		System.out.println();
	}
}