Compilare: user.cpp: In function ‘int main()’: 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("radixsort.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("radixsort.out","w",stdout); ^ user.cpp:13:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&a,&b,&c);v[1]=b; ^ In file included from /usr/include/string.h:642:0, from /usr/include/c++/4.8/cstring:42, from user.cpp:2: In function ‘void* memcpy(void*, const void*, size_t)’, inlined from ‘void radixsort(int)’ at user.cpp:29:32: /usr/include/i386-linux-gnu/bits/string3.h:52:71: warning: call to void* __builtin___memcpy_chk(void*, const void*, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest)); ^