void save_into_file(){
	
	STRING* read_str = ""; STRING* write_str = ""; 
	STRING* before_str = ""; STRING* after_str = "";
	
	var fhandle = file_open_read("map.dat");
	if(fhandle == NULL){ error("File wasn't found!"); return; }
	
	var len_var = file_length(fhandle);	
	file_str_readto(fhandle, read_str, ";", len_var);	
	file_close(fhandle);
	
	// BEFORE string:
	var start_var = str_stri(read_str, "[ROOM 2]");
	str_cut(before_str, read_str, 0, start_var + 7);
	
	// AFTER string:
	var end_var = str_stri(read_str, "[ROOM 3]");
	str_cut(after_str, read_str, end_var, len_var);
	
	// get the part of the string, where we need to change stuff:
	str_cut(write_str, read_str, start_var + 8, end_var - 1);
	str_cpy(write_str, "THIS IS NOT THE SECOND ROOM!");
	
	// add empty space:
	str_cat(before_str, " ");
	// use that empty space to move pointer to the next line:
	str_setchr(before_str, str_len(before_str), 10);
	
	// add empty space to the stuff we've changed:
	str_cat(write_str, " ");
	// add changes to BEFORE string:
	str_cat(before_str, write_str);
	// use empty space at the end to move pointer to the next line:
	str_setchr(before_str, str_len(before_str), 10);
	// add AFTER str (so the whole string is complete now)
	str_cat(before_str, after_str);
	
	// write this all into the file:
	var fhandle = file_open_write("map.dat");
	file_str_write(fhandle, before_str);
	file_close(fhandle);
}