Compilare: user.cpp: In function ‘void radixsort()’: user.cpp:41:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < sizeof(numbers[0]);i++){ ^ user.cpp: In function ‘int main()’: user.cpp:17:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin); ^ user.cpp:18:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out","w",stdout); ^ user.cpp: In function ‘void read()’: user.cpp:25:38: 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); ^