How to Split a String by a Delimiter in C?

Splitting a string by a delimiter is a common task in programming. In C, strings are arrays of characters, and there are several ways to split them based on a delimiter. In this article, we will explore different methods to split a string by a delimiter in C.

Splitting Strings in C

The strtok() method splits str[] according to given delimiters and returns the next token. It needs to be called in a loop to get all tokens. It returns NULL when there are no more tokens.

Syntax of strtok()

char *strtok(char *str, const char *delims);

Parameters

• str: It is the pointer to the string to be tokenized.
• delims: It is a string containing all delimiters.

Return Value

• It returns the pointer to the first token encountered in the string.
• It returns NULL if there are no more tokens found.

C program for splitting a string

C Program to demonstrate how to split a string using strtok().

// C program for splitting a string
// using strtok()
#include <stdio.h>
#include <string.h>

int main()
{
    char str[] = "Geeks-for-Geeks-is-a-computer-science-portal";

    // Returns first token
    char* token = strtok(str, " - ");

    // Keep printing tokens while one of the
    // delimiters present in str[].
    while (token != NULL) {
        printf(" % s\n", token);
        token = strtok(NULL, " - ");
    }

    return 0;
}

 Geeks
 for
 Geeks
 is
 a
 computer
 science
 portal

Time complexity : O(n)

Auxiliary Space: O(n), where n is the number of characters in the string.