October 4, 1999 - Literals
October 4, 1999|
Tips: October 1999
Yehuda Shiran, Ph.D.
Integer literals are whole numbers that have no decimal point or fractional part. They can be positive, negative, or equal to zero. Decimal integers are written with ten digits, 0 through 9. Except for the number 0, a decimal integer cannot have a leading 0 digit.
Octal integers use eight digits, 0 through 7. Octal integers are written with a leading zero (the digit 0). The decimal integer 10 would be written as 012 in octal math.
Hexadecimal integers are commonly used in programming environment because each hexadecimal digit represents four binary bits. Hexadecimal integers are written with 16 digits, 0 through 9 and A (equal to 10) through F (equal to 15). The prefix for hexadecimal numbers is
0X. Note that number notation is case insensitive. You can see hexadecimal notation in HTML's color specification:
There are two digits for each of the three main colors: red, green, and blue (RGB). Two digits can represent 16 * 16 = 256 different colors.
Floating point numbers (sometimes called real numbers) have a fraction part. The decimal point distinguishes between integer and floating literals. The literal
16 is an integer, while the literal
16.0 is a float. Additionally, a floating point number may include an exponent specification of the form
e-exp. Here are some floating point numbers:
-13.3 0.056 4.2e19 // equal to 4.2 * 1019 -3.1E12 // equal to -3.1 * 1012 .1e12 // equal to 0.1 * 1012 2E-12 // equal to 2 * 10-12
Boolean literals are
true value can usually be replaced by any nonzero integer, but it is not recommended. Likewise, the
false value can usually be replaced by zero integer, but it is not recommended as well.
document.write("<FONT COLOR='red' SIZE='4'>");