Difference between null strings and empty strings in C++

In this article, we will discuss the difference between the Null Strings and Empty Strings in C++. But before discussing their differences, we must know about the Null Strings and Empty Strings with their example.

What is the Null String?

A pointer that does not specify anything or has the value nullptr is called a null string. In C++, the null pointer can be specified as nullptr. It doesn't refer to any specific memory location. Attempts to access or specify a null pointer often result in unknown behavior, which can cause a program to crash.

Null strings are typically used when working with pointers to a string or character array.

Null Pointer in C++:

A pointer that does not point to any object is known as a null pointer in C++. Literal nullptr acts as its representation. The nullptr function indicates that there is currently no valid object in memory to which the pointer points.

• A pointer that does not point to any valid string is called a null string.
• Null strings are often used to indicate this when there is no valid string pointer.
• For example, a function may return nullptr to indicate that a valid string does not exist when it returns a string pointer but cannot find the intended return string.

Handling Null Strings:

• Before attempting to specify a pointer when handling null strings, ensure it is indeed nullptr. Missing a reference to a null pointer can cause a program to crash and result in undefined behavior.
• Therefore, defensive programming techniques require us to always check for null before reading or modifying the string in question.

Initialization:

In order to show that null strings aren't now pointing to any legitimate strings, they may be explicitly initialized to nullptr.

Program:

Let us take an example to illustrate the Null strings in C++.

Output:

What is the Empty String:

A string without characters is called an empty string. A string literal with no characters in double quotes ("") or an empty string object are two ways to express an empty string in C++.

Empty String Literal:

An empty string literal in C++ is simply double quotes separated by using space. It presents a string that has no characters in it.

Empty String Object:

Another way to create an empty string in C++ is to construct a std::string object using default, which sets the string's preliminary state to empty.

Use:

• When a significant string is unavailable, empty strings are often used as placeholders or to indicate that there is no content.
• They are regularly used as default values for string variables, input/output operations, and textual content manipulation.

Comparison:

• In C++, an empty string is although be a valid string item although it lacks characters.
• It means that empty strings can be used for the same string operations and manipulations as non-empty strings.

Character Representation:

• An empty string takes up memory space to hold the null terminator character ('/0'), which shows the string's termination, even though it incorporates no visible characters.
• In C-style string operations, this null terminator individual is needed to suggest the end of the string.

Program:

Let us take an example to illustrate the Empty String in C++.

Output:

Key difference between Null string and Empty String in C++:

There are several differences between the Null Strings and Empty Strings in C++. Some main differences between the Null Strings and Empty Strings are as follows: