Floating-Point Literals

Floating-point numbers can be represented in a number of ways. The following are all legitimate floating-point numbers :

1003.45	.00100345e6	100.345E+1100345e “2
1.00345e3	0.00100345e+6

Floating-point literals have several parts , which appear in the following order as shown in Table 3.9.

Table 3.9. Floating-Point Literal Requirements

Part	Is It Required?	Examples
Whole Number	Not if fractional part is present.	0, 1, 100, 1003
Decimal Point	Not if exponent is present; must be there if there is a fractional part.
Fractional	Cannot be present if there is no decimal point; must be there if there is no whole number part.	0, 1, 1415927
Exponent	Only if there is no decimal point.	e23, E “19, E6, e+307, e “1
Type Suffix	No. The number is assumed to be double precision in the absence of a type suffix.	f, F, d, D

The following representations illustrate the ways you can specify a floating-point literal that is consistent with the requirements in Table 3.9:

1.234	(Whole Number) . (Fractional)
1E2	(Whole Number)(Exponent)
1.234F	(Whole Number) . (Fractional)(Type Suffix)
1E2D	(Whole Number)(Exponent)(Type Suffix)

The following restrictions apply to floating-point literals:

• Single precision floating-point literals produce compile-time errors if their values are non-zero and have an absolute value outside the range 1.40239846e “45f through 3.40282347e+38f.

• Double precision floating-point literals produce compile-time errors if their values are non-zero and have an absolute value outside the range 4.94065645841246544e “324 through 1.7976931348623157e+308.

Troubleshooting Tip

If you have trouble assigning floating-point literals to variables of type float , see "Floating-Point Literal Loss of Precision Error," in the "Troubleshooting" section at the end of this chapter.