View Compilation Error

0_0_39238937_4669.cpp: In function 'int main()':
0_0_39238937_4669.cpp:2:11: error: expected primary-expression before '=' token
    2 | #define PI=3.1415927
      |           ^
0_0_39238937_4669.cpp:10:30: note: in expansion of macro 'PI'
   10 |                 v = 4 / 3 *( PI * r * r * r);
      |                              ^~