How Arrays and Strings Work
An array lines up values of the same type in one continuous block of memory. Each value gets an index, starting from 0, and writing arr[i] retrieves the value at that position. A string is an array of characters. A null character is a character with value 0 that marks the end of a string. In C, it is written as \0 and placed at the end of the string.
If the string "HELLO" starts at address 200, what's the address of str[2]?