// iostream_cerr.cpp// compile with: /EHsc// By default, cerr and clog are the same as cout#include <iostream>#include <fstream> using namespace std; void TestWide( ) { int i = 0; wcout << L"Enter a number: "; wcin >> i; wcerr << L"test for wcerr" << endl; wclog << L"test for wclog" << endl; } int main( ) { int i = 0; cout << "Enter a number: "; cin >> i; cerr << "test for cerr" << endl; clog << "test for clog" << endl; TestWide( );}  

 Input  Sample Output Enter a number: 3test for cerrtest for clogEnter a number: 1test for wcerrtest for wclogcout The object controls insertions to the standard output as a byte stream. cerr extern ostream cerr; The object controls unbuffered insertions to the standard error output as a byte stream. Once the object is constructed, the expression cerr.flags() & unitbuf is nonzero.  cout extern ostream cout; The object controls insertions to the standard output as a byte stream.