C - Split Slows Down My Computer - c

Question

I'm trying to program a split that takes in a char-array with multiple words and separates each word into their own smaller char-array. All the pointers of the smaller char-arrays are kept in a pointer array so I can return a double pointer.
Can you take a look at my code and see if you see any errors. When I try to run my program my computer gets gradually slower, after 3-4 seconds I can't move my mouse or alt+f4 my editor. So something has to be seriously wrong!
Also I'm completely new to C-programming so I will most definitely have a silly mistake in there.
char **split(char *s) {
char **result;
int wrd_cnt = 2; //I'm adding NULL at the end of the pointer-array.
//Counts the number of words to allocate memory for the pointer-array.
for(int i = 0; i < strlen(s); i++) {
if(s[i] == ' ') {
wrd_cnt++;
}
}
result = malloc(wrd_cnt * sizeof(char*));
//Counts letters in each word to allocate memory for every single small char-array with malloc.
for(int i = 0; i < strlen(s); i++) {
for(int j = 0; j < (wrd_cnt); j++) {
int char_cnt = 0;
for(int k = 0; s[i] != ' ' || s[i] != '\0'; k++, i++) {
char_cnt++;
result[j] = malloc(char_cnt * sizeof(char));
}
}
}
//Puts each word into their own place in the pointer array.
for(int i = 0; i < strlen(s); i++) {
for(int j = 0; j < (wrd_cnt); j++) {
for(int k = 0; s[i] != ' ' || s[i] != '\0'; k++, i++) {
result[j][k] = s[i];
}
}
}
result[wrd_cnt-1] = NULL;
return result;
}

Answer 1

In this situation the loops using j and k can be removed and instead increment and reset i, j and char_cnt based on the i loop as the s array is processed, similar to what you had done for wrd_cnt in the first loop
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
char **split(char *s);
int main ( void) {
char **output = NULL;
int each = 0;
char line[99] = " string to parse for words ";
output = split ( line);
each = 0;
while ( output[each]) {
printf ( "%s\n", output[each]);
each++;
}
each = 0;
while ( output[each]) {
free ( output[each]);
each++;
}
free ( output);
exit ( 0);
}
char **split(char *s) {
char **result;
int wrd_cnt = 2; //I'm adding NULL at the end of the pointer-array.
int char_cnt = 0;
int i = 0;
int j = 0;
int k = 0;
//Counts the number of words to allocate memory for the pointer-array.
for(i = 0; i < strlen(s); i++) {
if(s[i] == ' ') {
wrd_cnt++;
}
}
if ( ( result = malloc(wrd_cnt * sizeof(char*))) == NULL) {
fprintf ( stderr, "malloc failure\n");
exit ( 1);
}
//Counts letters in each word to allocate memory for every single small char-array with malloc.
char_cnt = 1;
j = 0;
for( i = 0; i < strlen(s); i++) {
if ( s[i] == ' ') {
if ( ( result[j] = malloc(char_cnt * sizeof(char))) == NULL) {
fprintf ( stderr, "malloc failure\n");
exit ( 1);
}
j++;
char_cnt = 1;
continue;
}
char_cnt++;
}
if ( j == wrd_cnt - 2) {
//allocate for last word
if ( ( result[j] = malloc(char_cnt * sizeof(char))) == NULL) {
fprintf ( stderr, "malloc failure\n");
exit ( 1);
}
j++;
result[j] = NULL;
}
result[wrd_cnt - 1] = NULL;//just to make sure the last pointer is null
//Puts each word into their own place in the pointer array.
j = 0;
k = 0;
for( i = 0; i < strlen(s); i++) {
if ( s[i] == ' ') {
result[j][k] = '\0';//for space only so [j][0] is '\0'
k = 0;
j++;
continue;
}
result[j][k] = s[i];
k++;
result[j][k] = '\0';//for last word if there is no final space in s[]
}
return result;
}

Answer 2

Aside from the comments above your code scares me because of all the malloc() calls you do, one for each word. This means you must also free each word. This leaves programs open to memory leaks.
Given that this is C, which allows lots of casting, you can use a single malloc to hold both the (char *) pointer array AND the actual words.
char **split(char const *s) {
char **result; //
char *target; // where in result chars stored
size_t s_strlen = strlen(s); // length of s
int wrd_cnt = 2; //I'm adding NULL at the end of the pointer-array.
{
char const *sx;
for ( sx = s; sx = strpbrk( sx, " \t\n\r" ); sx++ )
{
wrd_cnt++;
}
}
result = malloc( (wrd_cnt * sizeof(char *)) + s_strlen + 2 );
/* allow for \0 and possible ' ' */
target = (char *)(result + wrd_cnt); /* where to save words */
strcpy( target, s ); /* copy to target known to be big enough */
if ( s_strlen > 0 && target[s_strlen-1] != ' ' )
strcat( target + s_strlen, " " ); /* assure ends in space */
{
char *tx, *tnext;
int n;
n = 0;
for ( tx = target; tnext = strpbrk( tx, " \t\n\r" ); tx = tnext + 1 )
{
result[n++] = tx; /* remember pointer */
*tnext = '\0'; /* terminate word */
}
result[n] = NULL; /* null termination */
}
return result;
}