Compilare: main.cpp: In function 'void construire(int, int, int, int)': main.cpp:15:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x1 <= x2 && y1 <= y2 && it <= s.length()) ~~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:55:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); i++) ~~^~~~~~~~~~