Char Array vs. Char Pointer in C: When Should I Use `char a[]` vs. `char *p` for Strings?

Array vs. Pointer in String Declarations: char a[] vs. char *p

In C programming, there's a distinction between declaring a character array and a character pointer when working with strings. The syntax you mentioned, "char a[] = string;" and "char *p = string;" demonstrates this difference.

Array Version: char a[] = string

This syntax declares an array of characters, 'a', whose size is determined automatically to accommodate the string literal "string". The array is initialized with the characters of the string, including the null-terminator. The array's size is known at compile time, allowing you to use the 'sizeof' operator to determine its length. You can modify the characters in the array later on.

Pointer Version: char *p = string

This syntax declares a pointer 'p' that points to the string literal "string". It's a faster approach than the array version, but modifying the characters pointed to by 'p' is prohibited since they reside in a read-only portion of memory. Modifying such string literals leads to undefined behavior.

Deprecation and Best Practices in C

In C , using string literals without the 'const' keyword has been deprecated. The preferred declaration for the pointer version is:

const char *p = "string";

Additionally, avoid using 'sizeof' to determine the size of strings pointed by pointers. Instead, use the 'strlen()' function.

Choosing Between Array and Pointer

The choice between using an array or a pointer depends on your scenario:

• For strings you don't intend to modify, use the pointer version for efficiency.
• For strings you plan to modify, use the array version.

Note for C

This distinction is specific to C and not applicable to C . In C, string literals can be used without 'const', but modifying them remains undefined behavior. In C , this usage is illegal.

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