Wyo VB Lecture Notes

Objective #1: Use the Math class methods.

• The Abs method can be used to compute the absolute value of a number as in
  
  intNum = Math.Abs(-3)
  
  which stores 3 into the variable intNum
  
  
• The Pow method can be used to compute base to an exponent as in
  
  intNum = Math.Pow(3, 4)
  
  which simplifies to 81 which is 3 to the fourth power. You should use the Pow method rather than the ^ operator.
  
  
• The Sqrt method can be used to compute a square root as in
  
  dblNum = Math.Sqrt(13)
  
  
• The Round met hod which uses Banker's Rounding (.5 only rounds up if the number before it is odd) - more info on Banker's Rounding
  
  intNum = Math.Round(13.5)
  
  rounds to 14 but
  
  intNum = Math.Round(12.5)
  
  rounds to 12.
  
  
• The Max and Min methods return the greatest or smallest value respectively.
  
  intNum = Math.Max(4, -6)
  
  causes 4 to be stored in intNum. While
  
  intNum = Math.Min(4, -6)
  
  causes -6 to be stored in intNum.
  
  
• The Floor method causes numbers to be changed to the next smallest integer
  
  intNum = Math.Floor(8.9)
  
  causes 8 to be stored in intNum while
  
  intNum = Math.Floor(-8.9)
  
  causes -9 to be stored in intNum.
  
  
• The Ceiling method causes numbers to be changed to the next greatest integer
  
  intNum = Math.Ceiling(8.1)
  
  causes 9 to be stored in intNum while
  
  intNum = Math.Ceiling(-8.9)
  
  causes -8 to be stored in intNum.
  
  
• The Log10, Sin, Cos, and Tan method compute base 10 logs, sines, cosines, and tangents respectively.
  
  intNum = Math.Log10(100)   causes 2 to be stored in intNum since 10 to the second power equals 100.
  dblNum = Math.Sin(3.14) causes 0 (or a number close to that) to be stored in dblNum since the sine of PI is 0.
  dblNum = Math.Cos(3.14) causes -1 to be stored in dblNum since the cosine of PI is -1.
  dblNum = Math.Tan(3.14/4) causes 1 to be stored in dblNum since the tangent of PI/4 is 1.
  
  
• Pretty accurate values for PI and e (Euler's constant) can be used since they are defined in the Math class as constants. The statement
  
  MessageBox.Show(Math.PI)   will display PI pretty accurately and
  MessageBox.Show(Math.E)  will display e pretty accurately.

Objective #2: Use the "macho" rounding formula to implement normal rounding rather than Banker's Rounding like the Math.Round method.

• Consider the following assignment statement
  
  intRounded = Math.Floor(dblUnrounded + 0.5)
  
  The value of intRounded will be value of dblUnrounded rounded to the nearest whole number with normal rounding
  
  
• Consider the following statement
  
  dblRounded = Math.Floor(dblUnrounded * 100 + 0.5) / 100
  
  The value of dblRounded will be value of dblUnrounded rounded to the nearest hundredth's place with normal rounding
  
  
• Only Mr. Minich calls this method of rounding "macho rounding". You will not see this algorithm referred to as macho rounding anywhere else.