Compilare: user.cpp: In function ‘int nth_element(int, int)’: user.cpp:54:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(arr[ i ] < p) i++; ^ user.cpp:56:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(arr[ j ] > p) j--; ^ user.cpp:65:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j >= k) return nth_element(li, j); ^ user.cpp: In function ‘void read()’: user.cpp:22:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:24:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &k); ^ user.cpp:26:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i = 1; i <= n; i++) scanf("%d", &arr[ i ]); ^