Compilare: user.cpp: In function ‘int main()’: user.cpp:34:13: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if(k&(k-1)==0) printf("0\n"); ^ user.cpp:30:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("kperm.in","r",stdin); ^ user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("kperm.out","w",stdout); ^ user.cpp:33:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^