CIS 250 - C-style strings

C-style strings are an array of characters
There must be room in the array for one more character (the null character) at the end of the string to indicate the end
The null character is specified by the sequence: '\0'
There is a library with functions that support C-style strings: #include <cstring>
No "using" statement is used since this is an old C library
Declaring a C-style string that can hold up to 199 characters: char buf[200];
Pointers are often used to refer to C-style strings: const char* msg = "Hello, world!";
You can access individual characters in a C-style string using array notation: buf[0] = 'h';
C++ string objects can use the .c_str() function to create an equivalent C-style string

The C library for characters is very useful with C-style strings: #include <cctype>
isalnum(ch) returns true iff ch is a letter or a digit
No "using" statement is used since this is an old C library
isalpha(ch) returns true iff ch is a letter
isblank(ch) returns true iff ch is a tab or a space
iscntrl(ch) returns true iff ch is a control character
isdigit(ch) returns true iff ch is a decimal digit
isgraph(ch) returns true iff ch has a graphical representation (which is the same as printable, but excludes the space character)
islower(ch) returns true iff ch is a lower case letter
isprint(ch) returns true iff ch is printable
ispunct(ch) returns true iff ch is a punctuation character
isspace(ch) returns true iff ch is a white-space character letter (such as tab, form feed, newline, space, etc.)
isupper(ch) returns true iff ch is an upper case letter
isxdigit(ch) returns true iff ch is a hexadecimal digit
tolower(ch) returns ch, but as a lower case version if it was upper case
toupper(ch) returns ch, but as an upper case version if it was lower case

Assume for the following that str1 and str2 are C-style strings (pointers to char arrays), ch is a char, and n in an int:

strlen(str1) returns the length of str1
strcpy(str1, str2) copies str2 to str1 [dangerous due to possible overflow]
strncpy(str1, str2, n) copies the first n characters from str2 to str1 and pads str1 with 0s if str2 is shorter than n characters [less dangerous than strcpy, but no terminating null is added to str1 if str2 if n or more characters long]
strcat(str1, str2) concatenates str2 to the end of str1 [dangerous due to possible overflow]
strncat(str1, str2, n) concatenates the first n characters of str2 to the end of str1 [dangerous due to possible overflow]
strcmp(str1, str2) returns an int less than 0 if str1 is less than str2, greater than 0 if str1 is greater than str2, or 0 if str1 equals str2
strncmp(str1, str2, n) does the same as strcmp, but only compares up to a maximum of n characters
strchr(str1, ch) returns a pointer to the first occurrence of ch in str1, or a null pointer if it is not found
strpbrk(str1, str2) returns a pointer to the first occurrence of any character in str2 within str1, or a null pointer if none is found
strstr(str1, str2) returns a pointer to the first occurrence of str2 in str1, or a null pointer if it is not found
strspn(str1, str2) returns the length of characters at the start of str1 which consist of only characters continaed in str2
strtok(str1, str2) is used to tokenize str1 based on the delimiter list in str2 - see documentation for details of use