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Articles on Trending Technologies
Technical articles with clear explanations and examples
Why C++ does not have a virtual constructor?
The virtual mechanism works only when we have a base class pointer to a derived class object.In C++, constructor cannot be virtual, because when constructor of a class is executed there is no virtual table in the memory, means no virtual pointer defined yet. So, the constructor should always be non-virtual.But virtual destructor is possible. Here is an exampleExample#include using namespace std; class b { public: b() { cout
Read MoreHow do I cast a type to a BigInt in MySQL?
You need to use the CAST operator along with CONV() function. The CONV() function can be used to convert one base number system to another base system.For Example, The 16 is one base system and 10 is another base system. The 16 base system is hexadecimal and 10 is a decimal.The syntax is as follows −SELECT CAST(CONV('yourColumnName', 16, 10) AS UNSIGNED INTEGER) as anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table castTypeToBigIntDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, ...
Read MoreHow to correctly implement END IF statement in a MySQL Stored Procedure?
The following is the syntax of END IF statement in MySQLIF yourCondition THEN yourStatement ELSE yourStatement END IFHere is the demo of END IF statement while creating a stored proceduremysql> DELIMITER // mysql> CREATE PROCEDURE Sp_Test( IN value INT ) - > BEGIN - > IF value < 10 THEN - > select 'Your value is less than 10'; - > ELSE - > select 'Your value is greater than 10'; - > END IF; ...
Read MoreReorder integer except for value 0 with MySQL?
To reorder integer except for value 0, use the below syntax −select *from yourTableName order by yourColumnName=0 ,yourColumnName;Let us first create a table −mysql> create table reorderIntegerExcept0 -> ( -> value int -> ); Query OK, 0 rows affected (0.70 sec)Following is the query to insert records in the table using insert command −mysql> insert into reorderIntegerExcept0 values(90); Query OK, 1 row affected (0.17 sec) mysql> insert into reorderIntegerExcept0 values(10); Query OK, 1 row affected (0.21 sec) mysql> insert into reorderIntegerExcept0 values(0); Query OK, 1 row affected (0.18 sec) mysql> insert into reorderIntegerExcept0 values(40); ...
Read MoreHow to generate different random numbers in a loop in C++?
Let us see how to generate different random numbers using C++. Here we are generating random numbers in range 0 to some value. (In this program the max value is 100).To perform this operation we are using the srand() function. This is in the C++ library. The function void srand(unsigned int seed) seeds the random number generator used by the function rand.The declaration of srand() is like below −void srand(unsigned int seed)It takes a parameter called seed. This is an integer value to be used as seed by the pseudo-random number generator algorithm. This function returns nothing.To get the number ...
Read MoreHow are virtual functions implemented in C++?
Virtual functions in C++ used to create a list of base class pointers and call methods of any of the derived classes without even knowing kind of derived class object. Virtual functions are resolved late, at runtime.Here is an implementation of virtual function in C++ program −Example#include using namespace std; class B { public: virtual void s() { //virtual function cout
Read MoreWhy is a smartphone called smart?
Why is a smartphone called smart? A very common question strikes our head every now and then when we hear- Smartphone? Well, why not? From internet browsing to road navigations and doing every possible thing online, it has really made our life easier. I don’t think the present smart phone addicted mankind can survive even a single day without its smartphones.What A Smartphone Can DoThese phones are no different than a mini computer. Very much similar to computers, these smartphones also runs on operating systems as well as there are different applications for performing specific tasks in it. Each app is ...
Read MoreEvaluation of Boolean expression
We write a program in 8085 in the assembly language just for the evaluation of only wo Boolean expressions of 4 variables by using the interface of logic controller. The output of the program should be logically tested automatically by the output by the input changing from the inputs from 0000, 0001, … to 1111 just to press any key.Let us say we want to evaluate the following Boolean expressions.First of all, truth table for the Boolean expressions is written down as shown in the following table.PQRSXY000010000100001010001100010010010100011010011100100001100101101010101100110000110111111000111100The inputs of the PQRS gets connected to PB3, PB2, PB1, and PB0 of ...
Read MoreJava Tuple setAt0() method for Unit class
The setAt0() method is used to set the Unit value in JavaTuples and a copy with a new value at index 0.Let us first see what we need to work with JavaTuples. To work with the Unit class in JavaTuples, you need to import the following package −import org.javatuples.Unit;Note − Steps to download and run JavaTuples program. If you are using Eclipse IDE to run Unit Class in Java Tuples, then Right Click Project ->Properties ->Java Build Path ->Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Unit; public class Demo { public static void main(String[] ...
Read MoreHow to use subList() in android CopyOnWriteArrayList?
Before getting into the example, we should know what CopyOnWriteArrayList is. It is a thread-safe variant of ArrayList and operations add, set, and so on by making a fresh copy of the underlying array.This example demonstrates about How to use subList() in android CopyOnWriteArrayListStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show CopyOnWriteArrayList elements.Step 3 − Add the following code ...
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