Friday, December 31, 2010

Karel -the Robot learns Java using Eclipse Tutorial

Posted by on Friday, December 31, 2010
Karel The Robot is a robot simulator that affords a gentle introduction to computer programming. Users write Karel programs and feed them to the simulator to watch them execute.

By solving karel problems you will build your logic and enjoy programming.



<-Karel 

Wednesday, December 29, 2010

Parent-Child Communication Using Pipes in UNIX

Posted by on Wednesday, December 29, 2010
This is the simplest of program that you can get.

Here the parent-child communicates over a pipe.

NOTE:
if the child wants to communicate to the parent then it will have to closes(fd[0]) and parent will closes(fd[1]).

this will only work UBUNTU, LINUX(RedHat) , Solaris, FreeBDS etc all UNIX VERSIONS. DONT TRY to use it on any compiler like gcc,turbo c, etc...

Send data from Parent to Child over a pipe:

Tuesday, December 28, 2010

Socket Programming in C (SERVER SIDE) Code

Posted by on Tuesday, December 28, 2010

In Unix Sockets help in network communication, so if u have any unix versions at your place try this program on the "vi-editor" and see the result. sockets help in network ipc.

Tuesday, December 21, 2010

Codeforces #47, Problem E

Posted by on Tuesday, December 21, 2010
1:  import java.io.BufferedReader;  
2:  import java.io.IOException;  
3:  import java.io.InputStreamReader;  
4:  import java.util.HashMap;  
5:  public class Main {  
6:       public static void main(String[] args) throws IOException {  
7:            BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));  
8:            String ans=bf.readLine();  
9:            String var[]=ans.split(" ");  
10:            HashMap<Integer, Double> val=new HashMap<Integer, Double>();  
11:            double dx=0;  
12:            int cnt=0;  
13:            double rt1=0;  
14:            double rt2=0;  
15:            val.put(null, (double)1);  
16:            val.put(null, (double) 2);  
17:            for(double i=1;i<=Integer.parseInt(var[0]);i++){  
18:                 for(double j=1;j<=Integer.parseInt(var[1]);j++){  
19:                      dx= Math.pow(2*i, 2)-(4*j);  
20:                      if(dx>0){  
21:                           rt1= (((-2*i)+ Math.sqrt(dx)))/2;  
22:                           rt2= (((-2*i) - Math.sqrt(dx)))/2;  
23:                           if(val.get(cnt)==null){  
24:                                cnt=cnt+1;  
25:                                val.put(cnt,(double)rt2);  
26:                           }  
27:                           if(val.get(cnt)==null){  
28:                                cnt=cnt+1;  
29:                                val.put(cnt,(double)rt1);  
30:                           }  
31:                           if(val.containsValue(rt1) &&val.containsValue(rt2)){  
32:                           }else if(val.containsValue(rt1)){  
33:                                cnt=cnt+1;  
34:                                val.put(cnt,(double)rt2);  
35:                           }else if(val.containsValue(rt2)){  
36:                                cnt=cnt+1;  
37:                                val.put(cnt,(double)rt1);  
38:                           }else{  
39:                                cnt=cnt+2;  
40:                           val.put(cnt,(double)rt1);  
41:                           val.put(cnt,(double)rt2);  
42:                           }  
43:                      }else if(dx==0){  
44:                           rt1=(double) ((-2*i)/2);  
45:                           if(val.get(1)==null){  
46:                                cnt=cnt+1;  
47:                                val.put(cnt,(double) rt1);       
48:                           }  
49:                           if(val.containsValue(rt1)){   
50:                           }else{  
51:                                cnt=cnt+1;  
52:                                val.put(cnt,(double)rt1);  
53:                           }  
54:                      }  
55:                 }  
56:            }  
57:            System.out.println(cnt);  
58:       }  
59:  }  

Monday, December 20, 2010

HashMap simple usage and understanding

Posted by on Monday, December 20, 2010
Map is an object that stores key/volume pairs. Given a key, you can find its value. Keys must be unique, but values may be duplicated.
The HashMap class uses a hash table to implementation of the map interface. This allows the execution time of basic operations, such as get() and put() to be constant.

An example is below:


Q. Find the numbers Divisible by an array of numbers ie div[] between a range ie from 1 to N?
Ans.  This can be solved using many ways, but we will be solving using HashMap which will help u understand the concept of HashMap in a better way..

NOTE:
For this u can use your command prompt, eclipse, netbeans or any IDE that supports JAVA. Using eclipse is much easier.


CODE :


1:  import java.util.HashMap; 

2:  public class Main { 

3:    public static int usingHashmap(int N,int div[]){ 

4:      int count=0; 

5:      HashMap<Integer, Integer> key=new HashMap<Integer, Integer>(); 

6:      for(int i=1;i<N;i++){ 

7:        key.put(i, i); 

8:      } 

9:      for(int i=0;i<div.length;i++){ 

10:        for(int k=1;k<N;k++){ 

11:        if(key.get(k)==null){ 

12:          key.put(k, -1); 

13:        } 

14:          if(key.get(k)%div[i]==0){ 

15:            count++; 

16:            key.remove(k); 

17:          } 

18:        } 

19:      } 

20:      System.out.println(count); 

21:      return count; 

22:    } 

23:    public static void main(String[] args) { 

24:      new Main().usingHashmap(50, new int[]{3,2}); 

25:    } 

26:  } 

Sunday, December 5, 2010

Detecting a Cookie

Posted by on Sunday, December 5, 2010
Here is a piece of code that can help people detect cookies. Cookies play an important part in the website.

*****************#####*****************
JS Code:
window.onload = showCookies;

function showCookies() {
    var outMsg = "";

    if (document.cookie == "") {
        outMsg = "There are no cookies here";
    }
    else {
        var thisCookie = document.cookie.split("; ");
        for (var i=0; i<thisCookie.length; i++) {
            outMsg += "Cookie name is '" + thisCookie[i].split("=")[0];
            outMsg += "', and the value is '" + thisCookie[i].split("=")[1] + "'<br />";
        }
    }
    document.getElementById("ELEMENT ID").innerHTML = outMsg;
}

*****************#####*****************

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