6.1 Numeric Literals

The simplest form of expression is a literal that denotes a primitive numerical value.

Integer Literals

Integer literals represent integers of type int. Integer literals are written in base 10 without any separators. Integer literals may contain a single negative sign. (The expression --1 is interpreted as the negation of the literal -1.)

The following list contains well-formed integer literals.

0, 1, -1, 256, -127098, 24567898765

Integer literals must have values that fall within the bounds for integer values (see section).

Integer literals may not contain decimal points (.). Thus the expressions 1. and 1.0 are of type real and may not be used where a value of type int is required.

Real Literals

A number written with a period or with scientific notation is assigned to a the continuous numeric type real. Real literals are written in base 10 with a period (.) as a separator and optionally an exponent with optional sign. Examples of well-formed real literals include the following.

0.0, 1.0, 3.14, -217.9387, 2.7e3, -2E-5, 1.23e+3.

The notation e or E followed by a positive or negative integer denotes a power of 10 to multiply. For instance, 2.7e3 and 2.7e+3 denote \(2.7 \times 10^3\), whereas -2E-5 denotes \(-2 \times 10^{-5}\).