View Compilation Error

0_0_31764012_2917.cpp:21:4: error: 'CP' does not name a type
    CP operator+(const CP&x)const {return (CP){a+x.a,b+x.b};}
    ^
0_0_31764012_2917.cpp:22:4: error: 'CP' does not name a type
    CP operator-(const CP&x)const {return (CP){a-x.a,b-x.b};}
    ^
0_0_31764012_2917.cpp:23:4: error: 'CP' does not name a type
    CP operator*(const CP&x)const {return (CP){a*x.a-b*x.b,a*x.b+b*x.a};}
    ^
0_0_31764012_2917.cpp:32:10: error: variable or field 'FFT' declared void
 void FFT(CP*a,int n,int inv){
          ^
0_0_31764012_2917.cpp:32:10: error: 'CP' was not declared in this scope
0_0_31764012_2917.cpp:32:13: error: 'a' was not declared in this scope
 void FFT(CP*a,int n,int inv){
             ^
0_0_31764012_2917.cpp:32:15: error: expected primary-expression before 'int'
 void FFT(CP*a,int n,int inv){
               ^
0_0_31764012_2917.cpp:32:21: error: expected primary-expression before 'int'
 void FFT(CP*a,int n,int inv){
                     ^