Appendix B Math Class

1
Appendix B Math Class

• Jim Fawcett
• CSE791 Advanced Windows Programming
• Summer 2002

2
Numeric Types C/.Net
3
Decimal

• A decimal number with 28 digits, or fewer, and 28
  decimal places, or fewer, will be stored
  exactly. x,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx
  
• Decimals are used mostly to represent money
  without roundoff errors.

4
Floating Point

• The range of valid Floats is -3.402823 x 1038
  lt float lt 3.402823 x 1038
• Smallest float greater than zero is 1.401298 x
  10-45
• Range of valid doubles is -1.79769313486232 x
  10308 lt double lt 1.79769313486232 x
  10308
• Smallest double greater than zero is
  4.94065645841247 x 10-324

5
Invalid Floating Point Numbers

• Operations on floats and doubles never throw
  exceptions.
• Dividing by zero results in infinity or
  infinity, depending on the sign of the
  numerator.
• Dividing zero by zero or infinity by infinity
  results in NAN, not-a-number, as does subtracting
  infinity from infinity.

6
Math Class

• The math class consists of all static methods and
  two constant fields PI 3.14159265358979 E
  2.71828182845905
• Most of the methods are defined only for
  doubles.
• Max and Min are defined for all numeric types
• Sign and Abs are defined for float, double,
  decimal, and all signed integer types

7
Modulus Operator, Methods

• Modulus operator in C result dividend
  divisorreturns the remainder after division,
  and is defined for all numeric types.
• Power double result Power(double base, double
  power)
• Exponential double result Exp(double power)
• Square Root double result Sqrt(double value)

8
Logarithms

• Log to base 10 double Log10(double value)
• Log to base e double Log(double value)
• Integer base double Log(double value, double
  base)

9
Trigonometric Methods

• double sin(double angle)
• double Cos(double angle)
• double Tan(double angle)
• double Asin(double value)
• double Acos(double value)
• double Atan(double value)
• double Atan2(double y, double x)
• double Sinh(double angle)
• double Cosh(double angle)
• double Tanh(double angle)

10
Appendix C String Theory

• string class
• Immutable
• Mutating functions return a new string
• Has read-only indexer access to individual chars
• Has Length property
• Methods returning a new string
• BinarySearch, CompareTo, Concat, Copy, Format,
  IndexOf (substring), Insert, LastIndexOf,
  PadLeft, PadRight, Remove, Replace, Sort,
  ToLower, ToUpper, Trim, TrimEnd, TrimStart
• Operators , , , , !,
• Assignment points to new string, loses old
  reference.

11
C Control Characters
12
StringBuilder

• StringBuilder Class
• Defined in System.Text
• Mutable
• Has property Length
• Has get, set indexer
• Methods
• Append, AppendFormat, Insert, Remove, Replace
• Operators
• , !,