Compilare: user.c: In function ‘main’: user.c:23: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:23: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:25: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:19: warning: ‘xr’ may be used uninitialized in this function user.c:19: warning: ‘yr’ may be used uninitialized in this function user.c:19: warning: ‘xj’ may be used uninitialized in this function user.c:19: warning: ‘yj’ may be used uninitialized in this function