Compilare: user.cpp: In function ‘int main()’: user.cpp:45:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<a[i].size();k++) ^ user.cpp:7:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("patrate5.in","r",stdin); ^ user.cpp:8:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("patrate5.out","w",stdout); ^ user.cpp:10:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&n); ^ user.cpp:42:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&p); ^