Compilare: user.cpp: In function ‘int main()’: user.cpp:79:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<g[nod].size();j++) ^ user.cpp:75:17: warning: unused variable ‘cost’ [-Wunused-variable] int cost=h.top().cost,nod=h.top().dest; ^ user.cpp:85:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<h2.size();i++) ^ user.cpp: In function ‘char nch()’: user.cpp:18:30: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf,BSIZE,1,si); ^