Update pi.c

C/pi.c

@@ -19,7 +19,6 @@ void main() {
    b = 0.75;
    c = 0.25;
    pi = 0;
-   pi = 0;
    for (i = 1; i <= NPTS; ++i)
       pi += a/((i-b)*(i-c));
    clock_gettime(CLOCK_REALTIME,&tend);