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Articles on Trending Technologies
Technical articles with clear explanations and examples
Replace one string with another string with Java Regular Expressions
To replace one string with another string using Java Regular Expressions, we need to use the replaceAll() method. The replaceAll() method returns a String replacing all the character sequence matching the regular expression and String after replacement.Declaration − The java.lang.String.replaceAll() method is declared as follows −public String replaceAll(String regex, String replaced) Let us see a program to replace one string with another string using Java Regular Expressions −Examplepublic class Example { public static void main( String args[] ) { String str = new String("Good Harry Good"); System.out.println( "Initial String : "+ str); ...
Read MoreC++ Program to Check Whether a Number is Palindrome or Not
A palindrome number remains the same if its digits are reversed i.e its value does not change. A palindrome number can also be called symmetric. For example: The numbers 12321, 1551, 11 etc are palindromes as they do not change even if their digits are reversed.A program that checks if a number is palindrome or not is as follows.Example#include using namespace std; void palindrome(int num) { int rev=0,val; val = num; while(num > 0) { rev = rev * 10 + num % 10; num = num / 10; } if(val==rev) cout
Read MoreCheck two numbers for equality in Java
To check two numbers for equality in Java, we can use the Equals() method as well as the == operator.Firstly, let us set Integers.Integer val1 = new Integer(5); Integer val2 = new Integer(5);Now, to check whether they are equal or not, let us use the == operator.(val1 == val2)Let us now see the complete example.Examplepublic class Demo { public static void main( String args[] ) { Integer val1 = new Integer(5); Integer val2 = new Integer(5); Integer val3 = new Integer(10); System.out.println("Integer 1 = "+val1); ...
Read MoreGet the list of all the public fields in Java
An array of field objects is returned by the method java.lang.Class.getFields(). These field objects include the accessible public fields of the class that is represented by the class object.Also, the getFields() method returns a zero length array if the class or interface has no public fields that are accessible or if a primitive type, array class or void is represented in the Class object.A program that demonstrates this is given as follows −Exampleimport java.lang.reflect.*; public class Demo { public static void main(String[] argv) throws Exception { Class c = java.lang.Thread.class; Field[] fields = ...
Read MoreC++ Program to Implement Sparse Matrix
A sparse matrix is a matrix in which majority of the elements are 0. An example for this is given as follows.The matrix given below contains 5 zeroes. Since the number of zeroes is more than half the elements of the matrix, it is a sparse matrix.5 0 0 3 0 1 0 0 9A program to implement a sparse matrix is as follows.Example#include using namespace std; int main () { int a[10][10] = { {0, 0, 9} , {5, 0, 8} , {7, 0, 0} }; int i, j, count = 0; int row = 3, col = 3; for (i = 0; i < row; ++i) { for (j = 0; j < col; ++j){ if (a[i][j] == 0) count++; } } cout
Read MoreRemoving a Preference from a Preference Node in Java
In order to remove a preference from a preference node in Java, we use the remove() method. The remove method() removes all the values associated with the specified key in the preference node.Declaration − The java.util.prefs.Preferences.remove() method is declared as follows −public abstract void remove (String key)where key is the key whose preference is to be removedThe remove methods throws the following exceptions −NullPointerExceptionThis exception occurs when the key is nullIllegalStateExceptionThis exception is thrown when the ancestor node is removed by the removeNode() method.Let us see a program to remove the preference from a preference node −Exampleimport java.util.prefs.Preferences; public class ...
Read MoreGregorian Calendar in Java
GregorianCalendar is a hybrid calendar that supports both the Julian and Gregorian calendar systems with the support of a single discontinuity, which corresponds by default to the Gregorian date when the Gregorian calendar was instituted.The java.util.GregorianCalendar class in Java is a concrete subclass of Calendar and provides the standard calendar system used by most of the world.Import the following package to work with GregorianCalendar class.import java.util.GregorianCalendar;The following are the constructors.Sr.No.Constructor & Description1GregorianCalendar() This constructs a default GregorianCalendar using the current time in the default time zone with the default locale.2GregorianCalendar(int year, int month, int dayOfMonth) This constructs a GregorianCalendar with the given ...
Read MoreJava Program to convert hexadecimal number to decimal number
Use the parseInt() method with the second parameter as 16 since it is the radix value. The parseInt() method has the following two forms.static int parseInt(String s) static int parseInt(String s, int radix)To convert hex string to decimal, use the 2nd syntax and add radix as 16, since hexadecimal radix is 16.Integer.parseInt("12", 16)Examplepublic class Demo { public static void main( String args[] ) { // converting to decimal System.out.println(Integer.parseInt("444", 16)); } }Output1092
Read MoreSpecify the TimeZone explicitly for Gregorian Calendar in Java
To specify the TimeZone explicitly, use the getTimeZone() method of the TimeZone class. For Locale and TimeZone, we have imported the following packages.import java.util.Locale; import java.util.TimeZoneLet us specify for timezone America/New_York.GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("America/New_York"), Locale.US);The following is an example.Exampleimport java.util.GregorianCalendar; import java.util.Locale; import java.util.TimeZone; public class Demo { public static void main(String[] a) { GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("America/New_York"), Locale.US); System.out.println(cal); } }Outputjava.util.GregorianCalendar[time=1542643323673, areFieldsSet=true, areAllFieldsSet=true, lenient=true, zone=sun.util.calendar.ZoneInfo[id="America/New_York", offset=-18000000, dstSavings=3600000, useDaylight=true, transitions=235, lastRule=java.util.SimpleTimeZone[id=America/New_York, offset=-18000000, dstSavings=3600000, useDaylight=true, startYear=0, startMode=3, startMonth=2, startDay=8, startDayOfWeek=1, start
Read MoreJava Program to convert octal number to decimal number
Use the parseInt() method with the second parameter as 8 since it is the radix value. The parseInt() method has the following two forms.static int parseInt(String s) static int parseInt(String s, int radix)To convert octal to decimal, use the 2nd syntax and add radix as 8, since octal radix is 8.Integer.parseInt("25", 8)The following is an example.Examplepublic class Demo { public static void main( String args[] ) { // converting to decimal System.out.println(Integer.parseInt("25", 8)); } }Output21
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