Compilare: main.cpp: In function 'void precalc()': main.cpp:18:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i<w.size(); i++) ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:35:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<s.size(); i++) ~^~~~~~~~~ main.cpp:41:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (k+1 == w.size()) ~~~~^~~~~~~~~~~