带进度条的圆周率计算

import math
import time
scale=20
t=time.process_time()
for i in range(scale+1):
  a,b='**'*i,'..'*(scale-i)
  c=(i/scale)*100
π=4*(4*math.atan(1/5)-math.atan(1/239))
print("%[{:3}{}->{}]".format(a,b,c))
time.sleep(0.1)
print(π)
print("{:.2f}s".format(t))
print("执行结束")