Neither if you are you are trying to get into the US by air. Its the CDC and actually results in being 11 since the day testing is considered day 0. Each country has their own requirements. I found that the US Embassy site in whatever country you test positive in provides helpful information.
“You tested positive for COVID-19.
Do not travel until a full 10 days after your symptoms started or the date your positive test was taken if you had no symptoms.” CDC.
If you think this is just a “recommendation” you are going to be very frustrated and upset when you can’t get a boarding pass to get into the US. “Airlines MUST refuse to board passengers who do not present a negative viral test result for COVID-19 (option A) or documentation of recovery from COVID-19 (option B)”. CDC. The Document of Recovery consists of the dated positive test result and a medical professional’s certification, signed and on letterhead that you have met the CDC’s requirement’s for travel. Been there, done that.
And the problem with not reporting Covid positive to your airline, just cancelling and wait for a negative test and rebooking on another airline is the cost of that ticket and how it will effect reimbursement for Covid related expenses including that cancelled ticket. Sometimes it’s easier and less costly to just do what you’re suppose to do.