#pragma once

/**
 * @brief get a substring of a string
 *
 * @param s string
 * @param pos first pos
 * @param l length
 * @return the substring
 */
char *get_substring(char *s, int pos, int l);

/**
 * @brief concatinate two strings
 *
 * @param s1 first
 * @param s2 second
 * @return the concatinated string
 */
char *concat(const char *s1, const char *s2);