Expression Evaluator
By Yonghe Yan, November 2006
Expression:
Result:
The Evaluator
The Expression Evaluator is a Java Applet that can
evaluate an expression with double precision floating
point decimal numbers. The applet uses double
to represent values during the evaluation. To evaluate
an expression with big integers, you may use the
Big Integer Expression
Evaluator, which uses java.math.BigInteger
to represent values.
The Expression
Any numbers and variables whose values have been saved
before can be used in the expression. The first character
of any number must be a digit or a zero. The order
of operations and available operators are listed as
follows:
|
|
Operator
|
Example
|
|
Assignment |
var = expression |
x=1+2*3 -> 7.0, and the value is saved
in variable x. |
|
Function |
see list below |
sin(pi/2) -> 1.0 |
|
Parenthesis, negative |
(expression), - |
(1+2)/5 -> 0.6 |
Exponentiation,
Modular exponentiation |
^,
m^e%n |
10^0.5 -> 3.1622776601683795,
65^5%119 -> 46.0 |
|
Multiplication, division, modulus |
*, /, % |
2/3 -> 0.6666666666666666 |
|
Addition, subtraction |
+, - |
1+2 -> 3.0 |
The Functions
Available functions are listed as follows:
| pi |
the double value that is closer than any other to pi. |
|
rand |
a random value, greater than or equal to 0.0 and less
than 1.0. |
| abs(x) |
the absolute value of x |
| acos(x) |
the arc cosine of x, in the range of 0.0 through pi. |
| asin(x) |
the arc sine of x, in the range of -pi/2 through pi/2. |
| atan(x) |
the arc tangent of x, in the range of -pi/2 through pi/2. |
| cbrt(x) |
the cube root of x. |
|
ceil(x) |
the smallest (closest to negative infinity) double
value that is greater than or equal to x and is equal
to a mathematical integer. |
|
cos(x) |
the trigonometric cosine of x. |
|
cosh(x) |
the hyperbolic cosine of x. |
| deg(x) |
Converts an angle measured in radians to an approximately
equivalent angle measured in degrees. |
|
exp(x) |
Euler's number e raised to the power of x. |
|
floor(x) |
the largest (closest to positive infinity) double
value that is less than or equal to x and is equal
to a mathematical integer. |
| ln(x) |
the natural logarithm (base e) of x. |
| log(x) |
the base 10 logarithm of x. |
| max(x, y) |
the greater of two values. |
| min(x, y) |
the smaller of two values. |
| mod(x, y) |
Computes the remainder operation on two arguments
as prescribed by the IEEE 754 standard. |
| rad(x) |
Converts an angle measured in degrees to an approximately
equivalent angle measured in radians. |
| rint(x) |
the value that is closest in value to x and is equal
to a mathematical integer. |
| sin(x) |
the trigonometric sine of x. |
| sinh(x) |
the hyperbolic sine of x. |
| sqrt(x) |
the correctly rounded positive square root of x. |
| tan(x) |
the trigonometric tangent of an angle. |
| tanh(x) |
the hyperbolic tangent of a double value. |
Source Codes
The source codes can download here:
BigIntegerExpression.zip.
You can use it for any purpose without restriction.
I do not guarantee that it is correct, so use it at
your own risk.
Permission is granted to copy and distribute source
codes, provided that the following credit line is
included: "Expression Evaluator, Yonghe Yan 2006."
Permission is granted to alter and distribute source
codes, provided that the following credit line is
included: "Adapted from Expression Evaluator, Yonghe
Yan 2006."