Programming | I Made Krisna's Times

24May/100

DataGridView DataSource C# Source Code

How to fill DataGridView items on c# if we're connect using OleDbConnection?

We're gonna use DataSet for filling the DataGridView.. Here'is the example...

The information about variables and objects used is

dataGridView1 --> DataGridView GUI Object from Toolbox
Program.con --> OleDbConnection (using System.Data.OleDb)
combo_produk_id --> ComboBox GUI Object from Toolbox

        private void Item_Load(object sender, EventArgs e)
        {
            dataGridView1.DataSource = null;
            DataSet ds = new DataSet();

            Program.con.Open();

            OleDbCommand cmd = Program.con.CreateCommand();
            cmd.CommandText = "SELECT * FROM produk";

            OleDbDataReader reader = cmd.ExecuteReader();
            combo_produk_id.Items.Clear();
            while (reader.Read())
            {
                combo_produk_id.Items.Add(reader.GetValue(0));
            }

            Program.con.Close();

            OleDbDataAdapter adapter = new OleDbDataAdapter(cmd);
            adapter.Fill(ds);

            dataGridView1.DataSource = ds.Tables[0];

        }

Tagged as: C, data, db, grid, ole, Programming, source, view No Comments

24May/100

Greedy Activity Selector C Source Code

The details of this problem can be find on my previous post : Greedy Activity Selector Java Source Code

First we must declare the function prototype

void recursiveActivitySelector(int*, int*, int, int, int*);
void greedyActivitySelector(int*, int*, int, int*);

Then here is the Recursive Solution of Greedy Activity Selector

void recursiveActivitySelector(int s[], int f[], int i, int j, int a[]){
     int m = i + 1;
     while (m < j && s[m] < f[i]){
           m = m + 1;
     }
     if (m < j){
           a[m] = 1;
           recursiveActivitySelector(s,f,m,j,a);
     }
}

And the Iterative Solution is

void greedyActivitySelector(int s[], int f[], int len, int a[]){
     int n = len;
     int i = 1;
     for (int m=1;m<n;m++){
         if (s[m] >= f[i]){
            a[m] = 1;
            i = m;
         }
     }
}

For testing the program, you can use main function like this

int main(){
    int a1[] = {1,0,0,0,0,0,0,0,0,0,0};
    int a2[] = {1,0,0,0,0,0,0,0,0,0,0};
    int s[] = {1,3,0,5,3,5,6,8,8,2,12};
    int f[] = {4,5,6,7,8,9,10,11,12,13,14};

    int len = sizeof(s) / sizeof(int);

    recursiveActivitySelector(s, f, 0, len, a1);
    printf("Recursive Solution : ");
    for (int i=0;i<len;i++){
        if (a1[i] == 1)
        printf("%d ",i+1);
    }

    printf("\n");

    greedyActivitySelector(s, f, len, a2);
    printf("Iterative Solution : ");
    for (int i=0;i<len;i++){
        if (a2[i] == 1)
        printf("%d ",i+1);
    }

    getch();
}

Tagged as: activity, algorithm, C, code, greedy, Programming, selector, source No Comments

24May/100

Greedy Activity Selector Java Source Code

Activity Selector is problem to choose which event will be choosen to get maximum number of event for using the resources (time). Each event has start time and finish time. Two or more event cannot use the resource at the same time.

And here is the recursive and iterative solution pseudocode based on Introduction to Algorithm, 2nd edition

RECURSIVE-ACTIVITY-SELECTOR(s, f, i, j)
1 m ← i + 1
2 while m  < j and sm < fi ▹ Find the first activity in Sij.
3     do m ← m + 1
4 if m < j
5    then return {am} ∪ RECURSIVE-ACTIVITY-SELECTOR(s, f, m, j)
6    else return Ø

GREEDY-ACTIVITY-SELECTOR(s, f)
1 n ← length[s]
2 A ← {a1}
3 i ← 1
4 for m ← 2 to n
5      do if sm ≥ fi
6            then A ← A ∪ {am}
7                 i ← m
8 return A

How about the implementation on java source code.... Let's check this out

    public static String recursiveActivitySelector(int[] s, int[] f, int i, int j){
        int m = i + 1;
        while (m < j && s[m] < f[i]){
            m = m + 1;
        }
        if (m < j){
            return Integer.toString(m+1) +" "+ recursiveActivitySelector(s, f, m, j);
        }
        else return "";
    }

And the iterative solution is....

    public static String iterativeActivitySelector(int[] s, int[] f){
        String a = "1";
        int i = 0;
        int n = s.length;

        for (int m=1;m<n;m++){
            if (s[m] >= f[i]){
                a = a + " " + (m+1);
                i = m;
            }
        }
        return a;
    }

Okay, that's it... Try and keep going with your work

Tagged as: activity, algorithm, code, greedy, Java, Programming, selector, source No Comments

23May/100

Java ResultSet to JTable

How to Show Java ResultSet to JTable?

First, let me write some requirements for this post

mysql-connector-java-5.1.x.jar (as a library for connecting mysql dan java)

Some import

import java.sql.ResultSet;
import javax.swing.table.DefaultTableModel;

And here is the method

    public static DefaultTableModel ResultSet2TableModel(ResultSet rs){
        try{
                DefaultTableModel dtm = new DefaultTableModel();
                ResultSetMetaData meta = rs.getMetaData();
                int col = meta.getColumnCount();

                rs.last();
                int row = rs.getRow();
                rs.beforeFirst();

                Object[] rowData = new Object[col];
                Object[] colData = new Object[col];

                for (int i=0;i<col;i++){
                    colData[i] = meta.getColumnLabel(i+1);
                }

                dtm.setColumnIdentifiers(colData);

                for (int i=0;i<row;i++){
                    rs.next();
                    for (int j=0;j<col;j++){
                        rowData[j] = rs.getString(j+1);
                    }
                    dtm.addRow(rowData);
                }

                return dtm;
        } catch (Exception ex){
            JOptionPane.showMessageDialog(null, "ResultSet to TableModel Converter : "+ex.getMessage());
            return null;
        }
    }

The return value is DefaultTableModel, you can use it like

ResultSet rs = con.executeQuery(sql);
DefaultTableModel dtm = ResultSet2TableModel(rs);
myJTable.setModel(dtm);

Note : I'm Using

NetBeans IDE 6.7
JDK 7
mysql-connector-java-5.1.6.jar
Windows XP SP3 Operating System

Tagged as: data, Java, jtable, Programming, query, resultset, show, source No Comments

22May/100

Node – Single LinkedList Java Source Code

Node is an object which is built for storing information and it’s has a door the the other node, so it’s not storing other node but just the way to the other node. If it is singleNode, that is the node which just has only one way to the other node.

LinkedList? LinkedList is a nodes which is connected each other. If linkedlist cosist of singleNode, we can say that linked list is single-LinkedList. If still being confused by linkedlist try to understand with array : Node == integer data, LinkedList == array, so if linkedlist consist of many integer data which is continued on memory alloctaion, linkedlist consist of nodes which is connected by the pointer to the other node.

public class singleNode {

    private Object info;
    public singleNode next;

    public singleNode(Object info){
        this.info = info;
        next = null;
    }

    public void setInfo(Object info){
        this.info = info;
    }

    public Object getInfo(){
        return this.info;
    }

    public Object popInfo(){
        Object temp = this.info;
        this.info = null;
        return temp;
    }

}

Tagged as: data, Java, linked, list, node, object, Programming, structure No Comments

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