How to split with multiple delimiters in C - c

Question

I have this line of text:
32+-#3#2-#3#3
I need to separate numbers from each other. So basically the result would be like this:
3
2+-
3
2-
3
3
This is my code but it's not working properly because I have numbers with two digits:
#include <stdio.h>
#include <string.h>
int main(void) {
char string[50] = "32-#3#2-#3#3";
// Extract the first token
char *token = strtok(string, "#");
// loop through the string to extract all other tokens
while (token != NULL) {
printf(" %s\n", token); //printing each token
token = strtok(NULL, "#");
}
return 0;
}

Answer 1

You can't do it with strtok (alone), because there is no delimiter between the numbers you want to split. It's easier without strtok, just print what you want printed and add a separator unless a character which belongs to the token follows:
#include <stdio.h>
int main()
{
char string[] = "32+-#3#2-#3#3";
for (char *token = string; *token; ++token)
if ('0'<=*token && *token<='9' || *token=='+' || *token=='-')
{
putchar(*token);
if (token[1]!='+' && token[1]!='-') putchar('\n');
}
}
If you consider this too easy, you can use a regular expression to match the tokens:
#include <stdio.h>
#include <regex.h>
int main()
{
char *string = "32+-#3#2-#3#3";
regex_t reg;
regcomp(&reg, "[0-9][+-]*", 0);
regmatch_t match = {0};
while (regexec(&reg, string+=match.rm_eo, 1, &match, 0) == 0)
printf("%.*s\n", (int)(match.rm_eo-match.rm_so), string+match.rm_so);
}

Answer 2

There is a simple way to achieve this, but in C is a bit more complicated since we don't have vector as in C++ but I can suggest a pure C implementation which can be improved:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void split_ss(const char* src,const char* pattern, char** outvec, size_t* outsize)
{
const size_t pat_len = strlen(pattern);
char* begin = (char*) src;
const char* next = begin;
if ((begin = strstr((const char*)begin, pattern)) != 0x00) {
unsigned int size = begin - next;
*outvec = malloc(sizeof(char) * size);
memcpy(*outvec , next, size);
outvec++;
(*outsize)+=1;
split_ss(begin+pat_len, pattern, outvec, outsize);
} else {
unsigned int size = &src[strlen(src)-1] - next + 1;
*outvec = malloc(sizeof(char) * size);
memcpy(*outvec, next, size);
(*outsize) += 1;
}
}
int main()
{
char* outdata[64] = {0};
size_t size, i=0;
split_ss("32+-#3#2-#3#3", "#", outdata, &size);
for(i=0; i < size; i++) {
printf("[%s]\r\n", outdata[i]);
}
// make sure to free it
return 0;
}
strstr is used to split by string rather than a character. Also output is a poorman 2D array with out size to iterate it and don't forget to free it.

Answer 3

strtok() is not the right tool for you purpose... As a matter of fact strtok() is rarely the right tool for any purpose because of its tricky semantics and side effects.
A simple loop will do:
#include <stdio.h>
int main(void) {
char string[50] = "32+-#3#2-#3#3";
for (char *p = string; *p; p++) {
if (*p == '#')
continue;
putchar(*p);
while (p[1] == '+' || p[1] == '-')
putchar(*++p);
putchar('\n');
}
return 0;
}