Compilare: main.cpp: In function 'bool rezolva(int)': main.cpp:55:20: warning: NULL used in arithmetic [-Wpointer-arith] while (s[poz]!=NULL) ^~~~ main.cpp: In function 'int main()': main.cpp:135:22: warning: NULL used in arithmetic [-Wpointer-arith] while(s[j]!=NULL) ^~~~ main.cpp:156:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<raspuns.size();i++) ~^~~~~~~~~~~~~~~