How to do that by while loop

Question

1,2,3,4,5,3,2,1
1,2,3,4,3,2,1
1,2,3,2,1
1,2,1
1

Answer 1

Looks like homework buddy.
Can you provide your attempt so we may guide you.
Providing a complete answer will not help you learn

Answer 2

♤♢☞ 𝐊𝐢𝐢𝐛𝐨 𝐆𝐡𝐚𝐲𝐚𝐥 ☜♢♤ ,
there should not be comma at each end of the line !?