Articles on Trending Technologies

Technical articles with clear explanations and examples

MySQL query to decrease value by 10 for a specific value?

Ankith Reddy
Ankith Reddy
Updated on 30-Jul-2019 696 Views

Let us first create a table −mysql> create table DemoTable    (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Score int    ); Query OK, 0 rows affected (0.89 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Score) values(67); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Score) values(78); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(Score) values(90); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(Score) values(56); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+----+-------+ ...

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Catch block and type conversion in C++

Smita Kapse
Smita Kapse
Updated on 30-Jul-2019 262 Views

In this section, we will see how to use the catch block for exception handling and the type conversion in C++.At first, let us see a code, and we will see what will be the output, and how they are generating.Example#include using namespace std; int main() {    try{       throw 'a';    }    catch(int a) {       cout

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Measure execution time with high precision in C/C++

Anvi Jain
Anvi Jain
Updated on 30-Jul-2019 2K+ Views

To create high precision timer we can use the chrono library. This library has high resolution clock. This can count in nanoseconds.In this program we will see the execution time in nanoseconds. We will take the time value at first, then another time value at the last, then find the difference to get elapsed time. Here we are using blank loop to pause the effect for sometimes.Example#include #include typedef std::chrono::high_resolution_clock Clock; main() {    auto start_time = Clock::now();    for(int i = 0; i

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How to make a class thread-safe in Java?

raja
raja
Updated on 30-Jul-2019 1K+ Views

A thread-safe class is a class that guarantees the internal state of the class as well as returned values from methods, are correct while invoked concurrently from multiple threads.The HashMap is a non-synchronized collection class. If we need to perform thread-safe operations on it then we must need to synchronize it explicitly.Example:import java.util.Collections; import java.util.HashMap; import java.util.Map; import java.util.Set; import java.util.Iterator; public class HashMapSyncExample {    public static void main(String args[]) {       HashMap hmap = new HashMap();       hmap.put(2, "Raja");       hmap.put(44, "Archana");       hmap.put(1, "Krishna");       ...

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Convert the column to a case-sensitive collation in MySQL?

Arjun Thakur
Arjun Thakur
Updated on 30-Jul-2019 652 Views

For this, you can use COLLATE. Following is the syntax −select *from yourTableName where yourColumnName LIKE yourValue COLLATE utf8_bin;Let us first create a table −mysql> create table DemoTable    (    LastName varchar(100)    ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Brown'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('BROWN'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable values('brown'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('BRoWN'); Query OK, 1 row affected (0.14 sec)Display all records ...

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Rint(), rintf(), rintl() in C++

Nishtha Thakur
Nishtha Thakur
Updated on 30-Jul-2019 248 Views

Here we will see three functions. These functions are Rint(), rintf() and the rintl(). These functions are used to convert floating point values into rounded format.The rint() FunctionThis function is used for rounding floating point value to integer. The syntax is like below. If the result is outside of return type, the domain error may occur. When the argument is 0 or infinity, then it will return unmodifiedfloat rint(float argument) double rint(double argument) long double rint(long double argument)Example#include #include using namespace std; main() {    double a, b, x, y;    x = 53.26;    y = 53.86; ...

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How to understand StringBuffer is thread-safe and StringBuilder is non-thread-safe in Java?

raja
raja
Updated on 30-Jul-2019 4K+ Views

StringBuffer(Thread-safe)StringBuffer is thread-safe meaning that they have synchronized methods to control access so that only one thread can access StringBuffer object's synchronized code at a time.StringBuffer objects are generally safe to use in a multi-threaded environment where multiple threads may be trying to access the same StringBuffer object at the same time.StringBuilder(Non-thread-safe)StringBuilder is not synchronized so that it is not thread-safe. By not being synchronized, the performance of StringBuilder can be better than StringBuffer.If we are working in a single-threaded environment, using StringBuilder instead of StringBuffer may result in increased performance. This is also true of other situations such as ...

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How to create Glue to fill the space between neighbouring components in Java?

Arjun Thakur
Arjun Thakur
Updated on 30-Jul-2019 662 Views

Let’s say we have 6 components and we need to fill the space between some of them −JButton button1 = new JButton("CSK"); JButton button2 = new JButton("DC"); JButton button3 = new JButton("MI"); JButton button4 = new JButton("SRH"); JButton button5 = new JButton("RR"); JButton button6 = new JButton("KKR");To fill the space and separate components, create a Glue using the createGlue() method −Box box = new Box(BoxLayout.X_AXIS); box.add(button1); box.add(button2); box.add(Box.createGlue()); box.add(button3); box.add(button4); box.add(Box.createGlue()); box.add(button5); box.add(button6);The following is an example to fill the space between neighbouring components −Examplepackage my; import java.awt.BorderLayout; import javax.swing.Box; import javax.swing.BoxLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JScrollPane; public class ...

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Generalized Lambda Expressions in C++14

Nishtha Thakur
Nishtha Thakur
Updated on 30-Jul-2019 388 Views

In C++11, the lambda was introduced. Lambdas are basically a part of code, that can be nested inside other function call statements. By combining lambda expressions with the auto keyword, they can be used later.In C++14, these lambda expressions are improved. Here we can get the generalized lambda. For example, if we want to create a lambda, that can add integers, add numbers, also concatenate strings, then we have to use this generalized lambda.Syntax of the lambda expression is looking like this:[](auto x, auto y) { return x + y; }Let us see one example to get the better idea.Example#include ...

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How to create an invisible fixed height component between two components in Java?

Chandu yadav
Chandu yadav
Updated on 30-Jul-2019 272 Views

Use the createVerticalStrut() method to create an invisible fixed height component between two components. Let’s say we have some button and we are creating a fixed height between them −box.add(button4); box.add(Box.createVerticalStrut(50)); box.add(button5); box.add(Box.createVerticalStrut(30)); box.add(button6);The following is an example to create an invisible fixed height component between two components in Java −Examplepackage my; import java.awt.BorderLayout; import javax.swing.Box; import javax.swing.BoxLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JScrollPane; public class SwingDemo {    public static void main(String args[]) {       JFrame frame = new JFrame("Groups");       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       JButton button1 = new JButton("CSK");       JButton button2 ...

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