Compilare: user.cpp: In function ‘void CountingSort(unsigned int*, unsigned int*, unsigned int)’: user.cpp:12:62: warning: operation on ‘i’ may be undefined [-Wsequence-point] for(; i != 0x100; index[++i] = index[~-i] + frequence[~-i]); ^ user.cpp:12:62: warning: operation on ‘i’ may be undefined [-Wsequence-point] user.cpp: In function ‘int main()’: user.cpp:37:40: 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:38:42: 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:42:41: 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); ^