https://python123.io/student/courses/5028/groups/64412/problems/programmings/6881#pagetop
import time
scale 50
print( 执行开始 .center(scale // 2, - ))
start time.perf_counter()
for i in range(scale 1):
a * * i
b . * (scale - i)
c (i / scale) * 100
dur time.perf_counter() - start
# 下面的 r 是回车键 将命令行的光标移动到所在行的开头 这样就实现了覆盖效果
print( r{:^3.0f}%[{}- {}]{:.2f}s .format(c, a, b, dur), end )
time.sleep(0.1)
print( n 执行结束 .center(scale // 2, - ))
