Compilare: user.cpp: In function ‘int main()’: user.cpp:10:9: warning: unused variable ‘i’ [-Wunused-variable] int i,j; ^ user.cpp:10:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j; ^ user.cpp:11:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("scalecrop.in","r",stdin); ^ user.cpp:12:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("scalecrop.out","w",stdout); ^ user.cpp:13:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&a,&b,&x,&y); ^