Available in the string.h header file are the following routines  
   
  strcat(string1,string2);
 
This joins string2 to string1; care must be taken to allocate enough space for the answer 
 
  strchr(string,character);
 
This locates the position of the first occurrence of the character within the string and returns the address of that character i.e. a Find 
 
  strcmp(string1,string2);
 
This compares string2 to string1, if no difference if found a NULL character is returned else the address of the first non matching character.
 
  strcpy(string1,string2);
 
The copies the string2 into string1
 
  strlen(string);
 
Returns the length of the string 
 
  isalpha(character);
 
Returns a non-zero number if the character is a letter, otherwise a zero is returned
 
  isupper(character);
 
Returns a non-zero number if the character is uppercase, otherwise a zero is returned
 
  islower(character);
 
Returns a non-zero number if the character is lower case, otherwise a zero is returned
 
  isdigit(character);
 
Returns a non-zero number if the character is a digit i.e. 0-9, otherwise a zero is returned
 
  toupper(character);
 
Returns the upper case version of the character 
 
  tolower (character);
 
Returns the lower case version of the character