Constant String in C

Constant String

A constant string in C is a string literal that is defined as a constant value. A constant string cannot be modified once it is defined.

The syntax for declaring a constant string is as follows:

const char *string_name = "string_value";

Explanation

• string_name is the name of the constant string
• "string_value" is the string literal that represents the value of the constant string.
• The const keyword is used to indicate that the string is a constant and cannot be modified.
• The type char * is used to declare a pointer to a string of characters.

Constant String - Example

The following code declares a constant string named greeting:

#include <stdio.h>

int main()
{
    const char *greeting = "Hello, World!";
    printf("%s\n", greeting);

    return 0;
}

Output:

Explanation

• The greeting string is declared as a constant and cannot be modified.
• The printf function is then used to print the contents of the greeting string to the console.

content

It's important to note that declaring a string as a constant only makes the pointer to the string a constant, not the contents of the string itself. Therefore, you should use the const keyword with caution when working with strings in C.

String Constant

A string constant in C is a sequence of characters surrounded by double quotes.

For example:

"Hello, World!"

• A string constant is treated as a string literal and has a type of char [].

• It is automatically null-terminated, which means that the end of the string is indicated by the special null character ('\0').

• The null terminator is not part of the string's length, but it is necessary for C to determine the end of the string.

• You can use string constants to initialize string variables or pass strings as arguments to functions.

String Constant - Example

#include <stdio.h>

int main()
{
    char greeting[20] = "Hello, World!";
    printf("%s\n", greeting);

    return 0;
}

Output:

Explanation

• The string constant "Hello, World!" is used to initialize the string variable greeting.
• The printf function is then used to print the contents of the greeting string to the console.

String Constant vs Constant String

Here's a table that summarizes the differences between a string constant and a constant string in C:

String Constant	Constant String
A string literal surrounded by double quotes ("string_value").	A string literal that is declared as a constant value using the const keyword (const char *string_name = "string_value";).
Automatically null-terminated ('\0').	Can be referenced by a constant pointer.
Not modifiable.	The pointer to the string is constant, but the contents of the string are not.