Compilare: main.cpp: In function 'int main()': main.cpp:33:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < c.size(); i++) ~~^~~~~~~~~~ main.cpp:36:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i < a.size()) val_a = a[i] - '0'; ~~^~~~~~~~~~ main.cpp:38:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i < b.size()) val_b = b[i] - '0'; ~~^~~~~~~~~~ main.cpp:68:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < pos.size(); k++) ~~^~~~~~~~~~~~