Before calling f: a[0] = 0.000000
Before calling f: a[1] = 2.000000
Before calling f: a[2] = 4.000000
Before calling f: a[3] = 6.000000
Before calling f: a[4] = 8.000000
Before calling f: a[5] = 10.000000
Before calling f: a[6] = 12.000000
Before calling f: a[7] = 14.000000
Before calling f: a[8] = 16.000000
Before calling f: a[9] = 18.000000
Before calling f: a[10] = 20.000000

After calling f: a[0] = 0.000000
After calling f: a[1] = 4.000000
After calling f: a[2] = 8.000000
After calling f: a[3] = 12.000000
After calling f: a[4] = 16.000000
After calling f: a[5] = 20.000000
After calling f: a[6] = 24.000000
After calling f: a[7] = 28.000000
After calling f: a[8] = 32.000000
After calling f: a[9] = 36.000000
After calling f: a[10] = 40.000000