(Thought question: ) Do you think that using float instead of double saves a significant amount of computer memory?

A good answer might be:

No. For most programs using variables of type double will cost only a few extra bytes in a program thousands of bytes long.

Explicit Floating Point Literals

Sometimes you need to explicily ask for a single-precision float literal. Do this by putting a lower case 'f' or upper case 'F' at the end, like this: 

123.0f        -123.5F         -198234.234f       0.00000381F

Sometimes you need to explicily ask for a double-precision double literal. Do this by putting a lower case 'd' or upper case 'D' at the end, like this: 

123.0d        -123.5D         -198234.234d       0.00000381D

Remember, that without any letter at the end, a floating point literal will automatically be of type double.

QUESTION 9:

Do you think that the following is legal? 

double rats = 8912D ;