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Articles on Trending Technologies
Technical articles with clear explanations and examples
Iterator vs forEach in Java
Collections can be iterated easily using two approaches.Using for-Each loop − Use a foreach loop and access the array using object.Using Iterator − Use a foreach loop and access the array using object.DifferencesConcurrentModificationException − Using for-Each loop, if an object is modified, then ConcurrentModificationException can occur. Using iterator, this problem is elliminated.Size Check − Using for-Each, size check is not required. Using iterator if hasNext() is not used properly, NoSuchElementException can occur.Performance − Performance is similar for both cases.Following is an example of using above ways.Exampleimport java.util.ArrayList; import java.util.Iterator; import java.util.List; public class Tester { public static ...
Read MoreC++ Program to Compute Combinations using Factorials
The following is an example to compute combinations using factorials.Example#include using namespace std; int fact(int n) { if (n == 0 || n == 1) return 1; else return n * fact(n - 1); } int main() { int n, r, result; coutn; coutr; result = fact(n) / (fact(r) * fact(n-r)); cout
Read MoreSet a duration in Java
To set a duration, let us declare two objects of Calendar classCalendar c1 = Calendar.getInstance(); Calendar c2 = Calendar.getInstance();Set a time for one of the calendar objectsc2.add(Calendar.HOUR, 9); c2.add(Calendar.MINUTE, 15); c2.add(Calendar.SECOND, 40);Now, find the difference between both the time. One would be the current time and another we declared above −long calcSeconds = (c2.getTimeInMillis() - c1.getTimeInMillis()) / 1000;The following is an example −Exampleimport java.util.Calendar; public class Demo { public static void main(String args[]) { Calendar c1 = Calendar.getInstance(); Calendar c2 = Calendar.getInstance(); // set hour, minute and second c2.add(Calendar.HOUR, 9); ...
Read MoreAdd seconds to current date using Calendar.add() method in Java
Import the following package for Calendar class in Java.import java.util.Calendar;Firstly, create a Calendar object and display the current date and time.Calendar calendar = Calendar.getInstance(); System.out.println("Current Date and Time = " + calendar.getTime());Now, let us increment the seconds using the calendar.add() method and Calendar.SECOND constant.calendar.add(Calendar.SECOND, 15);Exampleimport java.util.Calendar; public class Demo { public static void main(String[] args) { Calendar calendar = Calendar.getInstance(); System.out.println("Current Date = " + calendar.getTime()); // Add 15 seconds to current date calendar.add(Calendar.SECOND, 15); System.out.println("Updated Date = " + calendar.getTime()); } }OutputCurrent ...
Read MoreList the Interfaces That a Class Implements in Java
The interfaces that are implemented by a class that is represented by an object can be determined using the java.lang.Class.getInterfaces() method. This method returns an array of all the interfaces that are implemented by the class.A program that demonstrates this is given as follows −Examplepackage Test; import java.lang.*; import java.util.*; public class Demo { public static void main(String[] args) { listInterfaces(String.class); } public static void listInterfaces(Class c) { System.out.println("The Class is: " + c.getName()); Class[] interfaces = c.getInterfaces(); System.out.println("The Interfaces are: " + Arrays.asList(interfaces)); ...
Read MoreJagged Array in Java
Jagged array is a multidimensional array where member arrays are of different size. For example, we can create a 2D array where first array is of 3 elements, and is of 4 elements. Following is the example demonstrating the concept of jagged array.Examplepublic class Tester { public static void main(String[] args){ int[][] twoDimenArray = new int[2][]; //first row has 3 columns twoDimenArray[0] = new int[3]; //second row has 4 columns twoDimenArray[1] = new int[4]; int counter = 0; ...
Read MoreWrite a power (pow) function using C++
The power function is used to find the power given two numbers that are the base and exponent. The result is the base raised to the power of the exponent.An example that demonstrates this is as follows −Base = 2 Exponent = 5 2^5 = 32 Hence, 2 raised to the power 5 is 32.A program that demonstrates the power function in C++ is given as follows −Example#include using namespace std; int main(){ int x, y, ans = 1; cout > x; cout > y; for(int i=0; i
Read MoreCreate and demonstrate an immutable collection in Java
In order to create and demonstrate an immutable collection in Java, we use the unmodifiableCollection() method. This method returns an unmodifiable and immutable view of the collection.Declaration − The java.util.Collections.unmodifiableCollection() method is declared as follows -public static Collection unmodifiableCollection(Collection
Read MoreCopy characters from string into char Array in Java
Let’s say we have the following string.String str = "Demo Text!";To copy some part of the above string, use the getChars() method.// copy characters from string into chArray =str.getChars( 0, 5, chArray, 0 );The following is an example to copy characters from string into char Array in Java.Examplepublic class Demo { public static void main(String[] args) { String str = "Demo Text!"; char chArray[] = new char[ 5 ]; System.out.println("String: "+str); // copy characters from string into chArray str.getChars( 0, 5, chArray, 0 ); ...
Read MoreHow to schedule tasks in Java to run for repeated fixed-rate execution, beginning after the specified delay
One of the methods of the Timer class is void scheduleAtFixedRate(TimerTask task, long delay, long period). This method schedules the specified task for repeated fixed-rate execution, beginning after the specified delay.In fixed-rate execution, each execution is scheduled with respect to the scheduled run time of the initial execution. Fixed-rate execution is apt for repetitive activities that are respond to absolute time. Likewise, fixed-rate execution is appropriate for scheduling multiple repeating timer tasks that must remain in sync.Declaration − The java.util.Time.scheduleAtFixedRate(TimerTask task, long delay, long period) method is declared as follows −public void scheduleAtFixedRate(TimerTask task, long delay, long period)Here, task is ...
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