Compilare: user.cpp: In function ‘void Input()’: user.cpp:25:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 1; i <= N; ++i ) ^ user.cpp:27:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 1; i <= N; ++i ) ^ user.cpp:30:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 1; i <= N; ++i ) ^ user.cpp: In function ‘void BuildPI()’: user.cpp:41:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 2; i <= N; ++i ) ^ user.cpp: In function ‘int main()’: user.cpp:72:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 1; i <= Q; ++i ) ^ user.cpp:77:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = 1; j <= N; ++j ) ^