Compilare: main.cpp: In function 'int main()': main.cpp:55:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (ji = 0 ; ji < v[val[i].second].size() ; ji++){ ~~~^~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:23:25: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&n); ^ main.cpp:25:40: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d",&val[i].first); ^ main.cpp:29:34: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d",&x,&y); ^