char* repeat_char(char ch, size_t num_times) {
    char* s = malloc(sizeof(*s) * (num_times + 1));
    for(size_t i = 0; i < num_times; i++) {
        s[i] = ch;
    }
    // ▶ Whoops... forgot to write null terminator ('\0') ◀
    return s;
}

void print_string(char* s) {            //┌───────────────────────────────────┐
    for(int i = 0; s[i] != '\0'; i++) { //│ ▶▶▶ !!! CONDITIONAL JUMP… !!! ◀◀◀ │
        fputc(s[i], stdout);            //│     depends on unintialized value │
    }                                   //└───────────────────────────────────┘
}

int main(int argc, char* argv[]) {
    char* s = repeat_char('@', 3);
    print_string(s);
    free(s);
    return EXIT_SUCCESS;
}