What I mean is, you must remember to set the pointer to NULL or it won't work. Only pointers can be null (the C language defines it as all upper case: NULL), where null is a special address used to signify that the pointer is not pointing to any valid address in memory. We can use if statements to check whether a variable is null or not. This is not the same thing as NULL. Most likely, it’s printing 0 which is the typical internal null pointer value but again it can vary depending on the C compiler/platform. As an example: char name; The name array is null string. In C or C++, there is no special method for comparing NULL values. It’s also called ‘elvis-operato In this post, we will see how to check if an object is null in C#. Although the composite formatting feature can gracefully handle a null string, as the following example shows, attempting to call one if its members throws a NullReferenceException . That is not the same thing as a pointer pointing to NULL. A string will be null if it has not been assigned a value. There are there ways to check if an object is null in C# – 1. Usually, a pointer should point to some object which is … The null keyword is supported by the is statement. We can check null using the constant pattern. That’s still a character, and the string has a length of zero, but it’s not the same as a null string, which has no characters at all. It is used to check whether the specified string is null or an Empty string. In case if you want to assign a default value to any variable the time when it is null, then you can use Null Coalescing Operator(??). We will try to open a file in read mode, that is not present in the system. NULL and a null character are not the same thing. fill_foo checks if the pointer has a value, not if the pointer has a valid value. In C++, pointers are not guaranteed to be either NULL of have a valid value. We can check it using if statement. A string is null if it has not been assigned a value (in C++ and Visual Basic) or if it has explicitly been assigned a value of null. And if you remember, in other words if you know that the pointer is NULL, you won't have a need to call fill_foo anyway. That doesn’t mean that it has a null … The C++ language provides multiple low-level features to manipulate memory directly and specifies the concept of pointer, which is the object pointing to a memory address. The example is given below to explain the operator, Compare With nullptr to Check if Pointer Is NULL in C++. C doesn't have the general concept of null meaning a/any variable is unset or invalid. An empty string has a single element, the null character, '\0'. A null character is the character '\0'. Here we will see one program. Gridview checkbox is giving object cannot be cast from dbnull to other types if check box is not checked C# Object cannot be cast from DBNull to other types. ‘is’ constant pattern. Starting with C# 7.0, the is operator supports testing an expression against a pattern. So the function will return null value. It is used to check the null values. Let’s start with null-conditional operator – it’s ?.. Don’t you have a feeling that sometimes C# code goes too much in null-checking? Null-conditional / Elvis operator – ?. Check my C programming plzz it is not working correctly. A string contains a null character (or null terminator) which denotes the end of the string. Yep, me too. The Null Coalescing Operator is the binary operator that can have either True of False two values. But there are few C# 6 null-conditional operators that change it for good. A string will be empty if it is assigned “” or String.Empty (A constant for empty strings).. Syntax: public static bool IsNullOrEmpty(String str) In C#, IsNullOrEmpty() is a string method.