Defined in header <cstring> | ||
---|---|---|
char* strtok( char* str, const char* delim ); |
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 tostrtok
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
str == NULL
, the call is treated as a subsequent calls tostrtok
: the function continues from where it left in previous invocation. The behavior is the same as if the previously stored pointer is passed asstr
.
Parameters
str | - | pointer to the null-terminated byte string to tokenize |
delim | - | pointer to the null-terminated byte string identifying delimiters |
Return value
Pointer to the beginning of the next token or NULL
if there are no more tokens.
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.
Example
#include <cstring> #include <iostream> int main() { char input[100] = "A bird came down the walk"; char *token = std::strtok(input, " "); while (token != NULL) { std::cout << token << '\n'; token = std::strtok(NULL, " "); } }
Output:
A bird came down the walk
See also
finds the first location of any character from a set of separators (function) | |
returns the length of the maximum initial segment that consists of only the characters not found in another byte string (function) | |
returns the length of the maximum initial segment that consists of only the characters found in another byte string (function) | |
C documentation for strtok |
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