1. First of all, there is little difference between an integer and a long integer.

The biggest difference is that long integers will end in L (lowercase L).

For example, 28 is an integer, then 28l is a long integer, and its keyword is long.

2. Secondly, any constant containing several characters in ""is a string.

3. Then, floating-point numbers can only exist in decimal form. The difference between floating-point numbers and long floating-point numbers is the same as above, and an L (lowercase L) is added after long floating-point numbers.

For example, 123e2 is a floating-point number, and 123e2l is a long floating-point number, and they have a rule that there must be a number before e and an integer after e, and e can also replace e, which belongs to real number type.

4. In fact, Boolean type can be simply regarded as a conditional expression, that is, an expression that needs to be judged to be true or false.

1 is true and 0 is false.

There are only two Boolean values: false and true. The false serial number is 0, the real serial number is 1, and there are Boolean operations (or logical operations) for Boolean quantities.