White[385]% g++ namespace4.cpp
namespace4.cpp: In function 'int main()':
namespace4.cpp:28: error: 'i' was not declared in this scope
namespace4.cpp:29: error: 'j' was not declared in this scope
namespace4.cpp:36: error: redeclaration of 'int i'
namespace4.cpp:28: error: '<typeprefixerror>i' previously declared here
White[386]%