It is not forced conversion, but cout is not set. The 0 after 1.0 will be omitted. If the output of 1.7 is calculated, it will definitely not be converted into int.

To output 1.0, you need to set the precision of cout.

cout . precision(6)； ?

cout . setf(IOs::fixed)； ? ///output? 6? Decimal? Will it exceed the original decimal places? Make up 0? (will be rounded)?

cout？ & lt& lt？ 1.200? & lt& lt？ endl