std::strtok
Defined in header
<cstring>
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char* strtok( char* str, const char* delim );
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Finds the next token in a null-terminated byte string pointed to by str
. The separator characters are identified by null-terminated byte string pointed to by delim
.
This function is designed to be called multiples times to obtain successive tokens from the same string.
- If str != NULL, the call is treated as the first call to
strtok
for this particular string. The function searches for the first character which is not contained indelim
.
-
- If no such character was found, there are no tokens in
str
at all, and the function returns a null pointer. - If such character was found, is it the beginning of the token. The function then searches from that point on for the first character that is contained in
delim
.
-
- If no such character was found,
str
has only one token, and the future calls tostrtok
will return a null pointer - If such character was found, it is replaced by the null character '\0' and the pointer to the following character is stored in a static location for subsequent invocations.
- If no such character was found,
- The function then returns the pointer to the beginning of the token
- If no such character was found, there are no tokens in
- If str == NULL, the call is treated as a subsequent calls to
strtok
: the function continues from where it left in previous invocation. The behavior is the same as if the previously stored pointer is passed as str.
Contents |
[edit] Parameters
str | - | pointer to the null-terminated byte string to tokenize |
delim | - | pointer to the null-terminated byte string identifying delimiters |
[edit] Return value
Pointer to the beginning of the next token or NULL if there are no more tokens.
[edit] Notes
This function is destructive: it writes the '\0' characters in the elements of the string str
. In particular, a string literal cannot be used as the first argument of strtok
.
Each call to this function modifies a static variable: is not thread safe.
Unlike most other tokenizers, the delimiters in strtok
can be different for each subsequent token, and can even depend on the contents of the previous tokens.
[edit] Example
Output:
A bird came down the walk
[edit] See also
finds the first location of any character from a set of separators (function) |
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returns the length of the maximum initial segment that consists of only the characters not found in another byte string (function) |
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returns the length of the maximum initial segment that consists of only the characters found in another byte string (function) |
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C documentation for strtok
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