I need to concatenate records that match or are the same, we will concatenate column E, when column A and column H are the same as the previous record and we will concatenate only the previous record with the one that is the same as the previous record.

int concatenate_records(char last_record[], char current_record[], char buffer[]) {
    int word_count = 0;
    int i = 0;

    //First concatenate the previous and current record,
    //skipping the first column of the current record.
    for(i = 0; i < strlen(current_record); ++i) {
        if(current_record[i] == ',') {
            word_count++;
        }

        if(word_count == 0) continue;

        buffer[i] = current_record[i];
    }

    //add a comma after the concatenated strings.
    buffer[i] = ',';

    //Now, concatenate the last column of the previous record.
    int buffer_i = i + 1;
    int last_word = 0;
    for(i = 0; i < strlen(last_record); ++i) {
        if(last_record[i] == ',') {
            last_word++;
        }

        if(