The details about a pointer and array that showcase their difference are given as follows.PointerA pointer is a variable that stores the address of another variable. When memory is allocated to a variable, pointer points to the memory address of the variable. Unary operator ( * ) is used to ... Read More

A class method can be can be called using a NULL class pointer.Note − This is undefined behaviour and there is not guarantee about the execution of the program. The actual results depend on the compiler used.A program that demonstrates this is given as follows.Example Live Demo#include using namespace std; ... Read More

In C language both the global and static variables must be initialized with constant values. This is because the values of these variables must be known before the execution starts. An error will be generated if the constant values are not provided for global and static variables.A program that demonstrates ... Read More

Static C++ class members can be defined using the static keyword. The static member in a class is shared by all the class objects as there is only one copy of the static class member in the memory, regardless of the number of objects of the class.The static class member ... Read More

A class in C++ has public, private and protected sections which contain the corresponding class members.The private data members cannot be accessed from outside the class. They can only be accessed by class or friend functions. All the class members are private by default.The protected members in a class are ... Read More

Error-detecting codes are a sequence of numbers generated by specific procedures for detecting errors in data that has been transmitted over computer networks.When bits are transmitted over the computer network, they are subject to get corrupted due to interference and network problems. The corrupted bits leads to spurious data being ... Read More

To create a table with InnoDB engine, we can use the ENGINE command. Here is the query to create a table.mysql> create table EmployeeRecords - > ( - > EmpId int, - > EmpName varchar(100), - > EmpAge int, - > EmpSalary float - > )ENGINE=INNODB; Query OK, 0 rows ... Read More

To select last few days, use DATE_ADD() function in MySQL. The syntax is as follows −select date_add(curdate(), interval - anyIntgegerValue day);Or you can DATE_SUB() from MySQL.select date_sub(curdate(), interval anyIntgegerValue day);Or you can use the following syntax −select curdate() - interval anyIntgegerValue day;Here is the example of all syntaxes shown above ... Read More

To check whether a field is null or empty in MySQL, use the IF() function in MySQL. The syntax is as follows −SELECT IF(yourColumnName IS NULL or yourColumnName = '', 'NULLId', yourColumnName) as anyVariableName from yourTableName;To understand the above syntax, let us create a table. The following is the query ... Read More

The following is the process to simulate MySQL’s ORDER BY FIELD() in PostgreSQL.We have used an Online Compiler to run PostgreSQL.Let us now see what we did above to get the output.Firstly, we created a table.create table PostgreOrderIdDemo (    countryName varchar(20) );Inserted records with the help of INSERT command.insert ... Read More