strtok() function is a part of the <string.h> header file #include <string.h>
The syntax of strtok() function is as follows −
char* strtok(char* string, const char* limiter);
Input string string and a delimiter character limiter. strtok() will divide the string into tokens based on the delimited character.
We can expect a list of strings from strtok(). But, the function returns a single string because after calling strtok(input, limiter), it will returns the first token.
But we have to keep calling the function again and again on a NULL input string, until we get NULL! Generally, we used to keep calling strtok(NULL, delim) until it returns NULL.
Example
Following is the C program for strtok() function −
#include <stdio.h> #include <string.h> int main() { char input_string[] = "Hello Tutorials Point!"; char token_list[20][20]; char* token = strtok(input_string, " "); int num_tokens = 0; // Index to token list. We will append to the list while (token != NULL) { strcpy(token_list[num_tokens], token); // Copy to token list num_tokens++; token = strtok(NULL, " "); // Get the next token. Notice that input=NULL now! } // Print the list of tokens printf("Token List:\n"); for (int i=0; i < num_tokens; i++) { printf("%s\n", token_list[i]); } return 0; }
Output
When the above program is executed, it produces the following result −
Token List: Hello Tutorials Point!
Input string is “Hello Tutorials Point”, and we are trying to tokenize it by spaces.
We get first token by using strtok(input, " "). Here the double quotes are delimiter and are a single character string!
Afterwards, we keep getting tokens by using strtok(NULL, " ") and loop until we get NULL from strtok().