Compilare: user.cpp: In function ‘int main()’: user.cpp:86:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < nodes.size() && nodes[i].x_coord == nodes[0].x_coord) ^ user.cpp:89:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == nodes.size()) ^ user.cpp:92:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if(i+1 == nodes.size()){ ^