Compilare: user.cpp: In function ‘int main()’: user.cpp:26:113: warning: unused variable ‘maxlen’ [-Wunused-variable] int len0 = 0, len1 = 0, len2 = 0, len3 = 0, len4 = 0, len5 = 0, len6 = 0, len7 = 0, len8 = 0, len9 = 0, maxlen = 0; ^ 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.in", "r", stdin); ^ user.cpp:13:43: 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:15:38: 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); ^