strtok() in C: Split a String into Tokens

strtok() splits a modifiable C string into tokens using one or more delimiter characters. The first call receives the string; later calls pass NULL to continue from the previous position.

Syntax Top ↑

char *token = strtok(string, delimiters);
token = strtok(NULL, delimiters);

Split a Hyphen-Separated String Top ↑

#include <stdio.h>
#include <string.h>

int main(void) {
    char text[] = "Welcome-to-plus2net";
    char *token = strtok(text, "-");

    while (token != NULL) {
        printf("%s\n", token);
        token = strtok(NULL, "-");
    }

    return 0;
}

Output

Welcome
to
plus2net

Use Multiple Delimiter Characters Top ↑

#include <stdio.h>
#include <string.h>

int main(void) {
    char text[] = "apple, banana, orange. grape";
    char *token = strtok(text, ",. ");

    while (token != NULL) {
        printf("%s\n", token);
        token = strtok(NULL, ",. ");
    }

    return 0;
}

Output

apple
banana
orange
grape

Read the String and Delimiter Top ↑

#include <stdio.h>
#include <string.h>

int main(void) {
    char text[100];
    char delimiters[20];

    printf("Enter a string: ");
    if (fgets(text, sizeof(text), stdin) == NULL) {
        return 1;
    }

    printf("Enter delimiter characters: ");
    if (fgets(delimiters, sizeof(delimiters), stdin) == NULL) {
        return 1;
    }
    delimiters[strcspn(delimiters, "\n")] = '\0';

    char *token = strtok(text, delimiters);
    while (token != NULL) {
        printf("%s\n", token);
        token = strtok(NULL, delimiters);
    }

    return 0;
}

strtok() Changes the Original String Top ↑

strtok() writes null characters into the input array to terminate each token. Use a writable character array, not a string literal, and make a copy first if the original text must be preserved.

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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