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Dangling Pointers in C++

Dangling pointers Dangling pointers arise when an object is destroyed. Despite being deleted or de-allocated, it still has an incoming reference because the value of the pointer was not modified. The pointer still points to the memory location of the de-allocated memory. AVOID DANGLING POINTERS It is easy to avoid dangling pointer errors by setting the pointer to NULL... Continue Reading →

Void Pointer in C/C++

A void pointer or generic pointer is a special pointer that can point to objects of any datatype. It is declared just like a normal pointer by using void keyword at the time of declaration. void *p;

Size of a Pointer based on datatype

There is a lot of confusion about the size of the pointers based on datatypes. A usual question is if there is a difference of size in: int *p; char *p; string *p; The answer is simple. As we discussed in the previous detailed post on pointers, A Pointer points to the address of a... Continue Reading →

Boxing and Unboxing in C#

Boxing Boxing means to convert any value-type to object type or to any interface type implemented by this value type. When the CLR boxes a value type, it wraps the value inside a System.Object instance. In the following example,object o is boxing the integer first. int first=345; object o=first; UNBoxing Unboxing extracts or unwraps the value-type from... Continue Reading →

Difference between where and having clause

Having clause is used after group by clause whereas where clause is used before group by clauseHaving clause is used to filter the groups and where clause is used to filter rows Syntax select customer_id,Count(*) as visits from Customer_Info where age>25 group by customer_id having Count(*)>10

Copy Constructor

It is a constructor that creates an object by copying variables from another object of same class or we can simply say that it copies the data from one object into another object of the same class. It is a parameterized constructor that contains a parameter of the same class type. Syntax Teacher(const Teacher & obj){}

What is GemBox.Spreadsheet

GemBox.Spreadsheet is an easy to use .NET component that enables us perform different operations with spreadsheet files such as reading, writing, editing, converting and printing from the .NET applications using one simple API. GemBox.Spreadsheet is a fast and reliable component.

Difference between Coalesce and null if

Both are different yet confused most of the times. Coalesce() takes a list of values and returns the first non-null value. If there is no non-null value,it will return the null value whereas nullif() takes two values and returns the first value. If both values are equal, it returns null. See this example to understand in detail.

SQL Aliasing

SQL Aliases SQL aliases are actually temporary names given to tables or a column or columns in a table. They do not actually create a new column in the database, but are the temporary readable names given to columns or tables for the time of the execution of the query. So, they only exists for... Continue Reading →

Object Operators in PHP

Answer There are two object operators in PHP. The symbols are -> and :: -> Operator The object operator -> is used when you have to access an Instance property or call a method just like a dot (.) in other languages. For example, if there is a 'Students' class that includes the method 'Marks',... Continue Reading →

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