Understanding about "string" in c

Everything is based on a series of uniformly creasing addresses, to which each address has a binary value and that value corresponds to character in the ASCII table.

Character array and character pointer

What is the difference between character array and character pointer ?
Consider the following example:

char arr[] = "Hello World"; // array version
char ptr* = "Hello World"; // pointer version

The type of both the variables is a pointer to char or (char\*), so you can pass either of them to a function whose formal argument accepts an array of characters or character pointer. In C programming, the name of an array always points to the base address, roughly speaking, an array is a pointer.

Here are differences:

• 1 arr is an array of 12 characters. When compiler sees the statement:

  char arr[] = "Hello World";

  It allocates 12 consecutive bytes of memory and associates the address of the first allocated byte with arr. On the other hand when the compiler sees the statement.

  char ptr* = "Hello World";

  It allocates 12 consecutive bytes for string literal "Hello World" and 4 extra bytes for pointer variable ptr. And assigns the address of the string literal to ptr. So, in this case, a total of 16 bytes are allocated.

This library

In this library we have the following functions for manipulating strings:

• length: get the length of a string.
• equal: check if two strings are the same.
• copy: copy characters from one string to another string.
• subcopy: copy a specific portion of a string, using the starting index and an ending index, to another string.
• subcopy_len: copy a specific portion of a string, using the length, to another string.
• subcopy_index_len: copy a specific portion of a string, using the starting index and the length, to another string.