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