View Compilation Error

0_0_20188240_3364.cpp: In function 'int main()':
0_0_20188240_3364.cpp:2:12: error: expected primary-expression before '=' token
 #define pi = 3.1415927;
            ^
0_0_20188240_3364.cpp:8:34: note: in expansion of macro 'pi'
     v =(double) 4 / (double) 3 * pi * r * r * r;
                                  ^
0_0_20188240_3364.cpp:8:39: error: invalid type argument of unary '*' (have 'double')
     v =(double) 4 / (double) 3 * pi * r * r * r;
                                       ^