Tool functions for chars - c

Question

I want to handle some char variables and would like to get a list of some functions that can do these tasks when it comes to handling chars.
Getting first characters of a char (var_name[1] doesnt seem to work)
Getting last characters of a char
Checking for char1 matches with char2 ( eg if "unicorn" matches words with "bicycle"
I am pretty sure some of these methods exist in libraries such as stdio.h or so but google isnt my friend.
EDIT:My 3rd question means not direct match with strcmp but single character match(eg if "hey" and "hello") have e as common letter.

Answer 1

Use var_name[0] to get first character (array indexes run from 0 to N - 1, where N is the number of elements in the array).
Use var_name[strlen(var_name) - 1] to get the last character.
Use strcmp() to compare two char strings.
EDIT:
To search for character in a string you can use strchr():
if (strchr("hello", 'e') && strchr("hey", 'e'))
{
}
There is also strpbrk() function that would indicate if two strings have any common characters:
if (strpbrk("hello", "hey"))
{
}
Assuming you mean a char[], and not a char which is a single character.

Answer 2

C uses 0-based indexing, var_name[0] gives you the first char.
strlen() gives you the length of the string, which together with my answer to 1. means
char lastchar = var_name[strlen(var_name)-1]; http://www.cplusplus.com/reference/clibrary/cstring/strlen/
strcmp(var_name1, var_name2) == 0. http://www.cplusplus.com/reference/clibrary/cstring/strcmp/

Answer 3

I am pretty sure some of these methods exist in libraries such as
stdio.h or so but google isnt my friend.
The string functions in the C standard library (libc) are described in the header file . If you're on a unix-ish machine, try typing man 3 string at a command line. You can then use the man program again to get more information about specific functions, e.g. man 3 strlen. (The '3' just tells man to look in "section 3", which describes the C standard library functions.)

Answer 4

What you're looking for is the string functions in the C runtime library. These are defined in string.h, not stdio.h.
But your list of problems is simple:
var_name[0] works perfectly well for accessing the first char in an array. var_name[ 1] doesn't work because arrays in C are zero-based.
The last char in an array is:
char c;
c = var_name[strlen(var_name)-1];
Testing for equality is simple:
if (var_name[0] == var_name[1])
; // they match

Answer 5

C and C++ strings are zero indexed. The memory you need to hold a particular length string has to be at least the string length and one character for the string terminator \0. So, the first character is array[0].
As #Carey Gregory said, the basic string handling functions are in string.h. But these are only primitives for handling strings. C is a low level enough language, that you have an opportunity to build up your own string handling library based on the functions in string.h.
On example might be that you want to pass a string pointer to a function and also the length of the buffer holding that sane string, not just the string length itself.