97. Parse Comma-Separated Integers into an Array

#include <stdio.h>
#include <stdint.h>

void parse_csv_to_array(const char *str, uint8_t *arr, uint8_t *count) {
    // Your logic here
    char *head, *tail;
    uint8_t i=0;
    head= (char *)str;
    tail= (char *)str;
    while ((*head) != '\0') {
        if ((*tail) == ',') {
            *tail = '\0';
            sscanf(head, "%uh", &arr[i]);
            i++;
            *count = i;
            *tail = ','; // restore the comma
            tail++;
            head=tail;
        } 
        else if ((*tail) == '\0') {
            sscanf(head, "%uh", &arr[i]);
            i++;
            *count = i;
            head= tail;  // ready to terminate it
        }
        tail++;
    }
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    uint8_t arr[20];
    uint8_t count = 0;

    parse_csv_to_array(str, arr, &count);

    for (uint8_t i = 0; i < count; i++) {
        printf("%u", arr[i]);
        if(i < count - 1){
            printf(" ");
        }
    }
    return 0;
}

scan string looking for comma. 

once found , temporarily replace it by a '\0' to read the portion of string

once read put back the comma and move on

until the real end char '\0' is found, then you read it and stop the iteration.