What is the term for sending emails that imitate legitimate companies?

phishing it imitates the company email so that when you get on the mail it can collect all your data and then can begin to hack using your information such as password

Phishing refers to the malicious attack method by attackers who imitate legitimate companies in sending emails in order to entice people to share their passwords, credit card or other sensitive personal information. ... If you do surrender such information, the attacker will immediately capture your personal information.

which functions return a valid value without any arguments?

(-blank- and -blank- return a valid value without any arguments.)

1st -blank-

today

sqrt

count

2nd -blank-

round

now

sqrt