Compilare: user.cpp: In function ‘int main()’: user.cpp:4:104: 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),freopen("scalecrop.out","w",stdout),scanf("%d%d%d%d",&a,&b,&c,&d); ^ user.cpp:4:104: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] user.cpp:4:104: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]