Compilare: user.cpp: In function ‘void read()’: user.cpp:24:12: warning: unused variable ‘len’ [-Wunused-variable] int i, len, x, y, k; ^ user.cpp: In function ‘void dijkstra()’: user.cpp:44:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(node = 0; node < cost[c].size(); ++node) { ^ /tmp/ccHTN1kE.o: In function `read()': user.cpp:(.text+0x278): warning: the `gets' function is dangerous and should not be used.