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Keywords − Keywords in Java convey a special meaning to the compiler therefore, these cannot be used as identifiers. Java provides a set of 50 keywords.abstractcontinuefornewswitchassertdefaultgotopackagesynchronizedbooleandoifprivatethisbreakdoubleimplementsprotectedthrowbyteelseimportpublicthrowscaseenuminstanceofreturntransientcatchextendsintshorttrycharfinalinterfacestaticvoidclassfinallylongstrictfpvolatileconstfloatnativesuperwhileReserved words − Among the list of key words list mentioned above the key words goto and const are currently not in use. They are reserved words (for the future use).The true false and null − True, false and null represents certain values in Java, they are used as literals. They are not considered as keywords.Still, you cannot use them as identifiers in Java if you try to do so, a compile time error will ... Read More
The HTML DOM select Object represent the element of an HTML document.Let’s see how to create select objectSyntaxFollowing is the syntax −document.createElement(“SELECT”);PropertiesFollowing are the properties of select Object −PropertyExplanationautofocusIt returns and modify whether the drop-down list should get focused or not when page load.disabledIt returns and modify whether the drop-down list is disabled or not.lengthIt returns the number of elements inside a drop-down list in an HTML document.formIt returns the reference of the form that contain the drop-down list in the HTML document.multipleIt returns and modify whether multiple options can be selected from a drop-down list or not.nameIt returns ... Read More
Here we will see how to count number of matchsticks are required to make the pyramid-like below. The base of the pyramid is given. So if the base is 1, it will take 3 matchsticks to make a pyramid, for base 2, 9 matchsticks are needed, for base size 3, it will take 18 matchsticks.To solve this problem, we have to use this formula −Example Live Demo#include using namespace std; int main(){ int x; cout > x; int count = 3*x*(x+1)/2; cout
C++ boost libraries are widely useful library. This is used for different sections. It has large domain of applications. For example, using boost, we can use large number like 264 in C++.Here we will see some examples of boost library. We can use big integer datatype. We can use different datatypes like int128_t, int256_t, int1024_t etc. By using this we can get precision up to 1024 easily.At first we are multiplying two huge number using boost library.Example#include #include using namespace boost::multiprecision; using namespace std; int128_t large_product(long long n1, long long n2) { int128_t ans = (int128_t) n1 * ... Read More
One of the variant of the getConnection() method of the DriverManager class accepts url of the database, (String format) a properties file and establishes connection with the database.Connection con = DriverManager.getConnection(url, properties);To establish a connection with a database using this method −Set the Driver class name as a system property −System.setProperty("Jdbc.drivers", "com.mysql.jdbc.Driver");Create a properties object as −Properties properties = new Properties();Add the user name and password to the above created Properties object as −properties.put("user", "root"); properties.put("password", "password");Finally invoke the getConnection() method of the DriverManager class by passing the URL and, properties object as parameters.//Getting the connection String url = "jdbc:mysql://localhost/mydatabase"; Connection con = ... Read More
To query null value in MongoDB, use $ne operator. Let us first create a collection with documents −> db.queryingNullDemo.insertOne( ... { ... "StudentName":"Larry", ... "StudentDetails": ... { ... "StudentAge":21, ... "StudentSubject":"MongoDB" ... } ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5cd00bec588d4a6447b2e05f") } > db.queryingNullDemo.insertOne( ... { ... "StudentName":"Sam", ... "StudentDetails": ... { ... "StudentAge":23, ... ... Read More
To enable row selection, use the setRowSelectionAllowed () method and set it to TRUE −table.setCell setRowSelectionAllowed(true);The following is an example to enable row selection in a JTable −Examplepackage my; import java.awt.Color; import javax.swing.BorderFactory; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.border.TitledBorder; public class SwingDemo { public static void main(String[] args) { JFrame frame = new JFrame(); JPanel panel = new JPanel(); panel.setBorder(BorderFactory.createTitledBorder( BorderFactory.createEtchedBorder(), "ODI Rankings", TitledBorder.CENTER, TitledBorder.TOP)); String[][] rec = { { "1", "Steve", "AUS" }, ... Read More
Use GREATEST() to find the maximum. Let us first create a table −mysql> create table DemoTable1 ( Number int ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(80); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable1 values(229); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1 values(575); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;Output+--------+ | Number | +--------+ | 80 | | 229 ... Read More
Java provides two operators namely ++ and --, to increment and decrement values by 1 respectively.There are two variants of these operators −Pre-increment/decrement − This form, increments/decrements the value first, and then performs the specified operation.ExampleIn the following example, the initial value of the variable i is 5. We are printing the incremented value of it using the pre increment operator.Since we are using the pre increment operator, the value of i is incremented then printed. Live Demopublic class ForLoopExample { public static void main(String args[]) { int i = 5; System.out.println(++i); ... Read More
The inversions of an array indicate; how many changes are required to convert the array into its sorted form. When an array is already sorted, it needs 0 inversions, and in other case, the number of inversions will be maximum, if the array is reversed.To solve this problem, we will follow the Merge sort approach to reduce the time complexity, and make it in Divide and Conquer algorithm.InputA sequence of numbers. (1, 5, 6, 4, 20).OutputThe number of inversions required to arrange the numbers into ascending order.Here the number of inversions are 2. First inversion: (1, 5, 4, 6, 20) ... Read More