有进度条的圆周率

import math
import time
scale=50
s,m,=1,2
total,s,n,t=0.0,1,1.0,1.0
print("执行开始".center(scale//2, "#"))
start = time.perf_counter()
for i in range(scale+1):
    total+=t
    n+=2
    s=-s
    t=s/n
    k=total*4
    a = '*' * i 
    b = '.' * (scale - i)
    c = (i/scale)*100 
    dur = time.perf_counter() - start 
    print("\r{:^3.0f}%[{}->{}]{:.2f}s".format(c,a,b,dur),end='')
    time.sleep(0.2)
Pi=k
print("Pi值是{}".format(Pi))
print("\n"+"执行结束".center(scale//2,'*'))