Compilare: user.cpp: In function ‘int main()’: user.cpp:57:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d%d",&n,&m); ^ user.cpp:58:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1;i<=m;i++) {fscanf(f1,"%d%d",&x,&y);a[x].push_back(y);a[y].push_back(x);} ^