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Read time from internet time server - working java code

import java.io.*;
import java.net.*;
import java.util.*;

/**
 * This program makes a socket connection to the atomic clock in Boulder,
 * Colorado, and prints the time that the server sends.
 */
public class Time_Server_Socket_Test_Java {
    public static void main(String[] args) {
        try {
            Socket s = new Socket("time-A.timefreq.bldrdoc.gov", 13);
            try {
                InputStream inStream = s.getInputStream();
                Scanner in = new Scanner(inStream);

                while (in.hasNextLine()) {
                    String line = in.nextLine();
                    System.out.println(line);
                }
            } finally {
                s.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

iterate through map hashmap linkedhashmap in java

How to iterate through Map.. MashMap, LinkedHashMap ... in Java
Method 1 : If you're only interested in the keys, you can iterate through the keySet() of the map:

Map map = ...;

for (String key : map.keySet()) {
    // ...
}

Method 2 :

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java escape text in regular expression

Java's built‑in Pattern.quote() method lets you escape arbitrary text so it can be safely used in a regular expression.
For example, if a user enters "$5", you can match that exact string. Without escaping, the dollar sign would be interpreted as an end‑of‑line anchor. Use Pattern.quote() and the method wraps the text in \Q...\E quotes, ensuring every character is taken literally.

Here’s the one-liner :

Pattern.quote("$5");

use of @override annotation in java - why ?

The @Override annotation is your compile‑time guardian—it tells the compiler “I intend to override a parent method.” If there’s no matching superclass method, the compiler throws an error. See this example:


import java.util.HashSet;
import java.util.Set;
/**
 * Override_Annotation_Usage_Example, from  Effective Java
 */

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java reflection - what is - 101 tutorial

The name reflection is used to describe code which is able to inspect other code in the same system (or itself).

A simple code example of this in Java (imagine the object in question is foo) :

Method method = foo.getClass().getMethod("doSomething", null);
method.invoke(foo, null);

One very common use case in Java is the usage with annotations. JUnit 4, for example, will use reflection to look through your classes for methods tagged with the @Test annotation, and will then call them when running the unit test.

There are some good reflection examples to get started : at http://java.sun.com/developer/technicalArticles/ALT/Reflection/index.html

Bubble sort working source code - C/C++

#include <stdio.h>
#include <iostream.h>

void bubbleSort(int *array,int length)//Bubble sort function 
{
    int i,j;
    for(i=0;i<length;i++)
    {
        for(j=0;j<i;j++)
        {
            if(array[i]>array[j])
            {
                int temp=array[i]; //swap 
                array[i]=array[j];
                array[j]=temp;
            }
        }
    }
}

void printElements(int *array,int length) //print array elements
{
    int i=0;
    for(i=0;i<length;i++)
        cout<<array[i]<<endl;
}


void main()
{

    int a[]={9,6,5,23,2,6,2,7,1,8};   // array to sort 
    bubbleSort(a,10);                 //call to bubble sort  
    printElements(a,10);               // print elements 
}

C C++ CODE : Shooting method for solving boundary value problem

Working C C++ Source code program for Shooting method for solving boundary value problem

#include<iostream.h>
#include<conio.h>
float f1(float ,float,float);
float f2(float, float ,float);
int main()
{
    int i;

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C C++ CODE : Simpsons 1/3 rule for integration

Working C C++ Source code program for Simpsons 1/3 rule for integration

/************** SIPMPSONS 1/3 RULE ***********************/

#include<iostream.h>
#include<conio.h>
#include<math.h>
float funct(float a);
int main()
{
    char choice='y';
    float f,x,h,a,b,sum;
    clrscr();
    cout<<"a & b ? ";cin>>a>>b;
    do
    {
        sum=0;
        x=a;
        cout<<"Enter value of h ? ";cin>>h;
        while(x<b)
        {
            sum+=(funct(x)+4*funct(x+h)+funct(x+2*h));
            x=x+2*h;
        }
        cout<<endl<<"The integration is: "<<sum*h/3<<endl;
        cout<<endl<<"wanna continue (y/n) ? ";cin>>choice;
    }while(choice=='y');
    getch();
    return 0;
}

float funct(float x)
{
    return x*exp(x)-2;   // sin takes arguments in radian........
}

C C++ CODE : Trapezoidal rule for integration

Working C C++ Source code program for Trapezoidal rule for integration

/************* TRAPEZOID FULE FOR INTEGRATION *****************/
#include<iostream.h>
#include<conio.h>
#include<math.h>
float funct(float a);
int main()
{
    char choice='y';
    float f,x,h,a,b,sum;
    clrscr();
    cout<<"a & b ? ";cin>>a>>b;
    do{
        sum=0;
        x=a;
        cout<<"Enter value of h ? ";cin>>h;
        while(x<b)
        {
            sum+=(funct(x)+funct(x+h));
            x=x+h;
        }
        cout<<endl<<"The integration is: "<<sum*h/2<<endl;
        cout<<endl<<"wanna continue (y/n) ? ";cin>>choice;
    } while(choice=='y');
    getch();
    return 0;
}

float funct(float x)
{
    return x*exp(x)-2;   // sin takes arguments in radian........
}

C C++ CODE : Numerical integration for tabular data

Working C C++ Source code program for numerical integration - trapeziode and simpsons 1/3 method

/************************ INTEGRATION FOR TABULAR DATA *****************/
#include<iostream.h>
#include<conio.h>
int main()
{
    int n,i;
    float x[10],f[10],h,sum=0,a;
    clrscr();
    cout<<"No of datas ? ";cin>>n;
    cout<<"Enter datas : ";
    for(i=0;i<n;i++)
        cin>>x[i]>>f[i];
        
    for(i=0;i<n;i++)
    {
        if(i==0||i==n-1)
            sum+=f[i];
        else
            sum+=2*f[i];
    }
    h=x[1]-x[0];
    cout<<"The value using trapezoide: "<<h*sum/2;
    a=x[0];
    sum=0;
    while((a-h)<x[n])
    {
        sum+=(f[a]+4*f[a+h]+f[a+2*h]);
        a+=2*h;
    }
    cout<<"\nThe value using simpsons 1/3 is : "<<h*sum/3;
    getch();
    return 0;
}

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