Class int

Class int represents all integers (positive, negative and zero). In principle, there are no bounds on the value that can be represented by an int.

Perfect allows non-negative integer literals to be expressed in decimal format (e.g. 123), in binary (e.g. 0b1010) or in hexadecimal format (e.g. 0x4ac5). In the case of binary and hex formats, the letters may be any mixture of upper and lower case.

A construct such as -12 is not an integer literal, it is a minus-sign (representing the negation operator) followed by an integer literal.

The methods of class int include the following binary operators:

In each case, the second operand is also of type int and so is the result.

For the integer division and remainder operators, the divisor must be positive. This sort of restriction is called a precondition. We will discuss preconditions further in a later tutorial.

You can look up the preconditions for all the predefined operators of Perfect in the Library Reference page of the Language Reference Manual (look under the entry for the class of which the operator is a member, e.g. int).

The result of integer division is rounded towards minus infinity, and the result of the remainder operator is always in the range 0 to one less than the second operand. This means that the expression  (a/b)*b + a%b = a  is always true (remembering that  b  must always be positive).

For the exponentiation operator, the second operand must not be negative, and at least one of the operands must be non-zero.

Class int also defines the following unary operators:

Again, each of these yields another int.

The toString method of class int yields a string of decimal digits representing the integer. An int can be constructed from a string of decimal digits with an optional leading minus-sign, for example int{"123"} = 123.

Class int is a final class, so your own classes cannot inherit from it.

Next:  Enumeration classes