Convert date initially in character type to date

Question

There's a column with dates in my dataframe :

datemailing
25/04/2018
22/02/2018
22/02/2018
...

R considers that it's chr, so I'd like to convert it in date. I used :

attest$datemailing<-as.Date(attest$datemailing)

normally it works, but not this time. It converts the column in date, but displays :

datemailing
0025-04-20
0022-02-20
0022-02-20

Does anyone have an easy way to convert chr to date ?