Compilare: user.cpp: In function ‘int main()’: user.cpp:64:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = 0; j < coord_ox_go[i].size(); j++ ){ ^ user.cpp:74:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = 0; j < coord_ox_back[i].size(); j++ ){ ^ user.cpp:83:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = 0; j < coord_oy_back[i].size(); j++ ){ ^ user.cpp:92:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( j = 0; j < coord_oy_go[i].size(); j++ ){ ^