Compilare: user.cpp: In function ‘void erat(int)’: user.cpp:12:9: warning: unused variable ‘i’ [-Wunused-variable] int i=0; ^ user.cpp: In function ‘int main()’: user.cpp:49:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<p.size(); ++i){ ^ user.cpp:41:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dirichlet.in","r",stdin); ^ user.cpp:42:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dirichlet.out","w",stdout); ^ user.cpp:44:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&nf); ^