C Program to Split a String into a Number of Sub-Strings
In this article, we will learn how to split a string into a number of sub-strings using the C program.
The most straightforward method to split a string into substrings using a delimiter is by using strtok() function. Let’s take a look at an example:
#include <stdio.h>
#include <string.h>
void split(char *s, char *d) {
// Get the first substring
char *ss = strtok(s, d);
while (ss != NULL) {
printf("%s\n", ss);
// Get the next token
ss = strtok(NULL, d);
}
}
int main() {
char s[] = "Geeks,for,Geeks";
char *d = ",";
// Call the function to split and
// print substrings
split(s, d);
return 0;
}
Output
Geeks for Geeks
Explanation: strtok() splits the string into substrings using a comma as the delimiter. It modifies the original string in-place and returns each token (substring) one by one until there are no more tokens left.
There are also a few other methods in C on how to split a string into a number of sub-strings. Some of them are as follows:
Using a Loop and Manual String Copying
Manually traverse the string, copying each substring into a temporary string whenever we encounter a delimiter. This method doesn't modify the original string and allows more control over how the substrings are stored.
#include <stdio.h>
void split(char *s, char *d) {
int i = 0, j = 0;
char ss[50];
while (s[i] != '\0') {
// If current character is not delimiter
if (s[i] != d[0]) {
// Copy character to ss
ss[j++] = s[i];
} else {
ss[j] = '\0';
printf("%s\n", ss);
// Reset temp index for next substring
j = 0;
}
i++;
}
// Print the last substring
if (j > 0) {
ss[j] = '\0';
printf("%s\n", ss);
}
}
int main() {
char s[] = "Geeks,for,Geeks";
char *d = ",";
split(s, d);
return 0;
}
Output
Geeks for Geeks
By Replacing Delimiter by Null Character
Replace delimiter by null character '\0' and print the substring till this null character. After that, move pointer after this null character and print the substring till next null character. Keep doing this till the end of the string.
#include <stdio.h>
void split(char *s, char *d) {
// Pointer to start of current substring
char *ss = s;
// Loop through the string
while (*s) {
// If the delimiter is found
if (*s == d[0]) {
// Replace delimiter with null character
*s = '\0';
printf("%s\n", ss);
ss = s + 1;
}
s++;
}
// Print the last substring
if (*ss != '\0')
printf("%s\n", ss);
}
int main() {
char s[] = "Geeks,for,Geeks";
char *d = ",";
split(s, d);
return 0;
}
Output
Geeks for Geeks
