View Compilation Error

0_0_19174059_15511.cpp:3:8: error: macro names must be identifiers
 #define pi 3.1415927  
        ^
0_0_19174059_15511.cpp:4:5: error: 'nbsp' declared as reference but not initialized
 int main()  
     ^
0_0_19174059_15511.cpp:4:17: error: expected constructor, destructor, or type conversion before 'nbsp'
 int main()  
                 ^
0_0_19174059_15511.cpp:4:27: error: expected constructor, destructor, or type conversion before ';' token
 int main()  
                           ^
0_0_19174059_15511.cpp:5:1: error: expected unqualified-id before '{' token
 {  
 ^