A String is a NUL terminated array of chars. Remember to allow space in the string for the NUL, and for any new line character you may have too, if you dimension it manually. And remember to add a NUL back on to the end if you extend a string by adding individual characters to it.
There are lots of standard C function for handling strings - here's a categorised list of the more basic ones:
find next occurence
find previous occurrence of
find character in a string (first occurrence)
find character in a string (last occurrence)
find one string in another and return a pointer
locate one string in another
string compare ignore case
string compare - first "n" characters
compare first "n" characters of 2 strings, ignoring case
string copy (return a pointer)
join strings (concatenate)
copy first "n" characters of a string
join up to "n" character of one string to another
how many characters in a string are not within a specified set?
how many characters in a string are within a specified set?
how long is a string?
find a separator and return a pointer beyond it
string tokeniser (you should now use strsep)
* Regular expressions - regex.h
compile a regular expression then ...
... match a regular expression and ...
... free up any internal memory used.
handle regular expression error messages
Odd characters in the function name? Remember ...
c - compliment (not)
p - pointer
n - number / count
r - reverse (from end) (written 2010-06-30)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articlesC206 - C and C based languages - Character Strings 
Handling Binary data in Tcl (with a note on C) - (2007-09-09) 
Learning about Regular Expressions in C through examples - (2010-06-30) 
When is a program complete? - (2011-01-06) 
Setting up arrays in C - fixed size at compile time, or dynamic - (2011-01-24) 
Strings in C - (2011-01-25) 
Chars, char arrays and strings in C. Some early cautions and pitfalls. - (2012-01-26) 
Splitting a record into individual data values in C - (2012-05-04) 
Simple C structs - building up to full, dynamic example - (2014-12-03) 
Strings in C - strncmp strncpy and friends - (2015-10-27) 
String handling in C - new examples of extracting integers from a string - (2016-01-27)
Some other Articles
Local information for Melksham Hotel GuestsCatching up with an old friendObjects and Inheritance in C++ - an easy startString functions in CStaring a C course with Hello World - why?C Course exercise and sample answer - source in 2 filesJust pass a pointer - do not duplicate the dataSoftware versions used - June 2010Respecting our customers anonimity