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Programming Articles
Page 1560 of 2547
Difference between TreeMap, HashMap and LinkedHashMap in Java programming
HashMap, TreeMap and LinkedHashMap all implements java.util.Map interface and following are their characteristics.HashMapHashMap has complexity of O(1) for insertion and lookup.HashMap allows one null key and multiple null values.HashMap does not maintain any order.TreeMapTreeMap has complexity of O(logN) for insertion and lookup.TreeMap does not allow null key but allow multiple null values.TreeMap maintains order. It stores keys in sorted and ascending order.LinkedHashMapLinkedHashMap has complexity of O(1) for insertion and lookup.LinkedHashMap allows one null key and multiple null values.LinkedHashMap maintains order in which key-value pairs are inserted.Exampleimport java.util.HashMap; import java.util.Hashtable; import java.util.LinkedHashMap; import java.util.Map; import java.util.TreeMap; public class Tester { ...
Read MoreFormat floating point with Java MessageFormat
To format message with floating point fillers in Java, we use the MessageFormat class. The MessageFormat class gives us a way to produce concatenated messages which are not dependent on the language. The MessageFormat class extends the Serializable and Cloneable interfaces.Declaration −The java.text.MessageFormat class is declared as follows −public class MessageFormat extends FormatThe MessageFormat.format(pattern, params) method formats the message and fills in the missing parts using the objects in the params array matching up the argument numbers and the array indices.The format method has two arguments, a pattern and an array of arguments. The pattern contains placeholder in {} curly ...
Read MoreDifference between x++ and x= x+1 in Java programming
x++ automatically handles the type casting where as x= x + 1 needs typecasting in case of x is not an int variable. See the example below.Examplepublic class Tester { public static void main(String args[]) { byte b = 2; //Type casting is required //as 1 is int and b is byte variable b = (byte) (b + 1); System.out.println(b); byte b1 = 2; //Implcit type casting by the compiler b1++; System.out.println(b1); } }Output3 3
Read MoreConvert Java String Object to Boolean Object
A string object can be created in Java using the string literal.String myStr = “Amit”;Another way to create a string object is using the new keyword.String myStr = new String("Hello!");We have used the first method to create a string object.String str = "true";Now, use the valueOf() method to convert String Object to Boolean Object. We have used this method on Boolean object.Boolean bool = Boolean.valueOf(str);Let us now see the complete example to show how to convert String Object to Boolean Object.Examplepublic class Demo { public static void main(String[] args) { String str = "true"; ...
Read MoreCreate a Boolean object from Boolean value in Java
To create a Boolean object from Boolean value is quite easy. Create an object with Boolean and set the Boolean value “true” or “false”, which are the Boolean literals.Let us now see how “true” value is added.Boolean bool = new Boolean("true");In the same way, “False” value is added.Boolean bool = new Boolean("false");The following is an example displaying how to create a Boolean object from Boolean value.Examplepublic class Demo { public static void main(String[] args) { Boolean bool = new Boolean("true"); System.out.println(bool); bool = new Boolean("false"); System.out.println(bool); } }OutputTrue False
Read MoreGet week of month and year using Java Calendar
For using Calendar class, import the following package.import java.util.Calendar;Create a Calendar class object.Calendar cal = Calendar.getInstance();Now, get the week of month and year using the following fields.Calendar.WEEK_OF_MONTH Calendar.WEEK_OF_YEARThe following is an example.Exampleimport java.util.Calendar; public class Demo { public static void main(String[] args) { Calendar cal = Calendar.getInstance(); // current date and time System.out.println(cal.getTime().toString()); // date information System.out.println("Date Information.........."); System.out.println("Year = " + cal.get(Calendar.YEAR)); System.out.println("Month = " + (cal.get(Calendar.MONTH) + 1)); System.out.println("Date = " + cal.get(Calendar.DATE)); ...
Read MoreFormat hour in k (1-24) format in Java
The “k” format in Java Date is used to format hour in 1-24 format. Use SimpleDateFormat("k") to get the same format.// displaying hour in k format simpleformat = new SimpleDateFormat("k"); String strHour = simpleformat.format(new Date()); System.out.println("Hour in k format = "+strHour);Above, we have used the SimpleDateFormat class, therefore the following package is imported.import java.text.SimpleDateFormat;The following is an example −Exampleimport java.text.Format; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Calendar; public class Demo { public static void main(String[] args) throws Exception { // displaying current date and time Calendar ...
Read MoreC++ Program to Subtract Complex Number using Operator Overloading
Operator overloading can be done with most of the built-in operators in C++. The overloaded operators are functions with the keyword operator followed by the operator symbol that is defined. The overloaded operators have a return type and a parameter list like any function.A program that subtracts complex numbers using operator overloading is as follows −Example#include using namespace std; class ComplexNum { private: int real, imag; public: ComplexNum(int r = 0, int i =0) { real = r; imag = i; } ComplexNum operator - (ComplexNum const &obj1) ...
Read MoreFibonacci of large number in java
Fibonacci numbers of Fibonacci series grows exponentially and can be very large for large numbers like 500 or 1000. To handle such number, long data type is not sufficient. BigInteger can handle large number easily. BigInteger is useful in scenarios where calculations results in data which is out of limit for available primitive data types. See the example below of getting Fibonacci number of 100 and 1000.Exampleimport java.math.BigInteger; public class Tester { public static void main(String args[]) { System.out.println("Fibonacci of 100: "); System.out.println(fibonacci(100)); System.out.println("Fibonacci of 1000: "); ...
Read MoreChecking for a Leap Year using GregorianCalendar in Java
The GregorianCalendar.isLeapYear() method determines if the given year is a leap year. Returns true if the given year is a leap year.Firstly, import the following package to work with GregorianCalendar class.import java.util.GregorianCalendar;Now, check for a year by adding it as a parameter in the isLeapYear() method.gcal.isLeapYear(2012)The following is an example.Exampleimport java.text.ParseException; import java.util.GregorianCalendar; public class Demo { public static void main(String[] args) throws ParseException { GregorianCalendar gcal = new GregorianCalendar(); System.out.println("Is it a leap year? "+gcal.isLeapYear(2012)); } }OutputIs it a leap year? trueLet us see another example.Exampleimport java.text.ParseException; import java.util.GregorianCalendar; public class ...
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