Compilare: user.cpp: In function ‘int main()’: user.cpp:9:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("move.in","r",stdin); ^ user.cpp:10:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("move.out","w",stdout); ^ user.cpp:12:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:15:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^ user.cpp:22:20: warning: ‘last’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(int i=last+1;i<=n;i++) printf("%d %d\n",i,i-1); ^ user.cpp:20:24: warning: ‘first’ may be used uninitialized in this function [-Wmaybe-uninitialized] printf("%d\n",first-1+n-last); ~~~~~^~