Compilare: user.cpp: In function ‘int main()’: user.cpp:83:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < Res[i][j].size(); ++k){ ^ /tmp/cccEEy5q.o: In function `main': user.cpp:(.text.startup+0xc1): warning: the `gets' function is dangerous and should not be used.