Sunday, September 12, 2010

Sorting Arrays

// Interchange sort high to low
// assume n[] is 10 big and it contains 10 numbers and is 'int'
// compares each element with each one under it
// visualize it as 9 sorts on an array that is getting smaller
int g,r,c;
for ( r=0; r <=8; r++)
   {
     for ( g=r+1;g<=9;g++)
        {
            if ( n[r]  < n[g] )
               {
                   c=n[r];                // these 3 statements swap values
                   n[r] = n[g];          // in the 2 cells being compared 
                   n[g] = c;
                }
        }  
   } 

// bubble sort on the same array above
// compares pairs of elements during a pass
// an element can only move up one spot each pass
// finished if nothing was swapped or at most n-1 passes

int sw,r,c,g;
do
   {
   sw = 0; 
   for ( r=0; r <=8; r++)
      {
        g=r+1;
        if (n[r] <  n[g] )
          {
             c=n[r];              // next 3 statements swap 2 values
             n[r] = n[g];
             n[g] = c;
             sw=1;
          }
      }
    }  while ( sw = 1 }

// QUICK SORT is coming soon
// Sorting using pointer technique is coming

Variable Types

Variable Types

Since Variables stand for items that the program is manipulating
or playing with,  such as:
                        whole numbers       (small  normal   large)
                        fractional numbers        (small   large)
                        single characters
                        groups of characters as a unit
                         true / false conditions
 it is only logical to assume that JAVA gives the programmer  the

 capability to declare and use Variables that can hold each of the

above data types.  Remember that values ( or data ) being put into
Variables is the heart or basis of programming. 

Variables MUST be declared before they can be used in a program.

Common Variable types are as follows:
   short                     ... small integers
   int                          ... normal integers
   long                       ... big integers
   float                       ... small fractional numbers
   double                   ... big fractional numbers 
   char                       ... single character values   e.g.,     M    or   F
   string                     ... groups of characters viewed as a unit
   Boolean                 ... logical  TRUE  or  FALSE  values 

In object oriented and more sophisticated programs today, the
programmer can declare his or her own data type ( later )

Specifics concerning Java Data TYpes
NUMERIC (all numbers are signed)

short integer (16 bit number) --> i.e. 32,768
int integer (32 bit number) --> i.e. 2 billion or 2 x 109
long integer (64 bit number) --> i.e. 9 x 1018
float real (32 bit decimal) --> i.e. 1.4 x 10-45 to 3.4 x 1038
double real (64 bit decimal) --> i.e. 4.9 x 10-324 to 1.7 x 10308
  CHARACTER / STRING

char a unicode (2-byte) char
the String class handles multi-character strings (strings are unicode, as well). Strings are said to be immutable: updates to a String cause the new string to be created in memory (and pointed to by the String class). However the old string is not actually "updated", rather, its reference is lost (and it becomes available for garbage collection).  
BOOLEAN

boolean (with values true, false)  
DATE

the Date class measures the milliseconds since Jan 1, 1970 and provides supporting functions to interpret and manipulate date/times  
ARRAYS

arrays hold multiple instances of a data type or object

Programming Tuturials

visit this website :Programming Tutorial

click this for advance learning

Sorting an Array

Hello programmers.. my students.. i want to create a program in java that sort a number in descending order.

here is a sample program...
public class Sorting
{
    public static void main(String args[])
    {
        int arr[]={0,1,2,3,4,5,6,7,8,9,10};
        int temp=0;
       
        for(int i=0; i<10;i++)
        {
            for(int j=0; j<10; j++)
            {
                if(arr[j]
                {
                    temp=arr[j];
                    arr[j]=arr[j+1];
                    arr[j+1]=temp;
                }
            }
        }
       
        for(int x=0; x<10; x++)
        {
            System.out.println(arr[x]+ " ");
        }
    }
}


i hope you learn more in my blog,.... Think it Code it

Programming Tuturials

hello programmers.... hello students... java programmers.. visit this website to study advannce.

http://webpages.shepherd.edu/JROMANO/arrays.htm

Array Definition and samples

An array is multiple storage locations under one name. For now
we will talk about one and two dimensional arrays.

All the primitive data types that we have learned and used concerning
regular variables also apply to arrays.

int num = new int; // declare / initialize an integer variable

int nums[] = new int [10]; // declare and allocate space for 10 integer
// numbers. The 10 elements have the same
// name but each one will be referred to
// with a different subscript or position
// in the array. Thos array contains 10
// integer locations, number 0 thru 9

Anything that you can do with an integer variable, you can do with
each element of an integer array. But you must indicate which element
you are referring to.

e.g.. nums[0]=100;
nums[5]=200; etc.
JOptionPane.showMessageDialog(null,"answer is "+nums[2]);

Loops make working with arrays very easy.

for example:
int tot=100;
int n=0;
do
{
nums[n] = tot;
n=n+1;
} while (n <= 9 );

Remember that all rules that apply to variables of a specific type
also apply to each element of an array of that type.

Two dimensional arrays adhere to all the rules noted above, except
any reference to a two dimensional array must have 2 subscripts.

int numbers[] [] = new int [5] [10];

The above array has 5 rows and 10 columns.
The rows are numbered 0 thru 4, and the columns are numbered 0 thru 9.


Any reference to the array will have 2 subscripts and the first one will be
the row and the second one will be the column.

e.g.. numbers[1][3] = 100;

Loops are very useful with two dimensional arrays just like one
dimensional arrays, but a lot of the times nested loops are used
because of the nature of two dimensional arrays.

e.g.. int tot=10;
for(int a=0;a<=4;a++)
{
for(int b=0;b<=9;b++)
{
numbers[a][b] = tot;
tot=tot+10;
}
}

.
arrays can be declared but still need to be explicitly initialized
int [] dataPoints; // declares the array of integer
dataPoints = new int[10] ; // allocates array size (now usable)
dataPoints = new int[numPoints]; // allocates array size with size specified by a run-time variable
an array can be re-initialized (with the same data type) at runtime, at which point old array entries are discarded
Java standard arrays cannot are not dynamically resizable like arrays in Visual Basic or PowerBuilder (i.e. where the language can dynamically extend the array, if needed). Java throws an exception if an out-of-bounds array index is referenced. Java.util's Vector class provides dynamic array-like capability (a Vector can store a collection of any type of object). The standard Vector class does not, however, limit data to a specific data type (data type limitation capability has to be built in a Vector extension).

Wednesday, September 8, 2010

Array sample program

hello world.. hello programmers... i want to share to you how to make a sample program array using java..

I hope you learn and enjoy reading my blog...

import java.io.*;

public class javaarray
{
public static void main(String args[])
{
int x[]=new int[3];

x[0]=100;
x[1]=200;
x[2]=300;

//display result

System.out.println("The array[0]=" + x[0]);
System.out.println("The array[1]=" + x[1]);
System.out.println("The array[2]=" + x[2]);

}
}

next time i will post another sample program using array. using loop to print the array element.