就照着书写的还是不行，怎么回事

#include<iostream>
int main()
{
int x=5;
int y=7;
std:: cout<<endl;
std:: cout<<x+y<<" "<<x*y;
std:: cout<<endl;
return 0;
}
error C2065: 'endl' : undeclared identifier
执行 cl.exe 时出错.
这个是在VC++6.0里运行的
D:\未命名2.cpp In function 'int main()':
7 14 D:\未命名2.cpp [Error] 'endl' was not declared in this scope
7 14 D:\未命名2.cpp [Note] suggested alternative:
39 0 c:\program files (x86)\dev-cpp\mingw32\lib\gcc\mingw32\4.8.1\include\c++\iostream In file included from c:\program files (x86)\dev-cpp\mingw32\lib\gcc\mingw32\4.8.1\include\c++\iostream
1 D:\未命名2.cpp from D:\未命名2.cpp
564 5 c:\program files (x86)\dev-cpp\mingw32\lib\gcc\mingw32\4.8.1\include\c++\ostream [Note] 'std::endl'
这个实在DEVc++里运行的