Compilare: user.cpp: In function ‘int main()’: user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("simpla.in","r",stdin); ^ user.cpp:32:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("simpla.out","w",stdout); ^ user.cpp:34:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); a--; ^