Compilare: user.cpp: In function ‘int main()’: user.cpp:80:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1;i<=strlen(s);i++) ^ user.cpp:75:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("blis.in","r",stdin); ^ user.cpp:76:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("blis.out","w",stdout); ^ user.cpp:78:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%s",&k,s); ^