Compilare: user.cpp: In function ‘int main()’: user.cpp:17:53: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortnet.in","r",stdin),scanf("%d%d",&n,&m); ^ user.cpp:17:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] user.cpp:20:63: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("<%d,%d>",&l,&h),--l,--h,a[i][l].u=h,a[i][h].u=l; ^