[R] strftime - Dates from Excel files

[Ana]

Hi

I have many excel files were the Date field was not declared as date,
so the dates look like this: 1/2/1978
I know that the format is day/month/year

How can I make R change this to Date format?

If I use strftime, I get wrong dates:

dataset=c("1/2/1978")

strftime(dataset,"%d/%m/%Y")
"19/02/0001"


Thanks in advance.