动态实现进度条

import time
a="开始下载"
m="下载完成"
print(f"{a:=^54}")
j=1
for i in range(0,101,2):
    if j<=50:
        b="*"*j
        c="."*(50-len(b))
        j+=1
    print(f"\r{i}%[{b}{c}]",end=' ')
    time.sleep(0.1)
print()
print(f"{m:=^54}")