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# Section 3.6 PowerPoint PPT Presentation

Section 3.6. BUILT-IN FUNCTIONS involving numbers & strings. Functions - terminology. Functions are called from within a procedure. e.g., Sqr(x) is a function call A function receives 1 or more input values & returns a unique output value n = Left (string, 3).

Section 3.6

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## Section 3.6

BUILT-IN FUNCTIONS

involving numbers & strings

### Functions - terminology

• Functions arecalled from within a procedure.

• e.g., Sqr(x) is a function call

• A function receives 1 or more input values & returns auniqueoutput value

n = Left (string, 3)

Output assigned to n

Function name

input

• Sqr

• Int

• Round

• Rnd

### Numeric functions - Sqr

• Sqr (n) : returns the square root of n.

• requires exactly one positive numeric input value

• may contain an expression for n

• Examples: assumen = 25

Sqr (16) returns 4

Sqr (2) returns 1.414214

Sqr (n) returns 5

Sqr (n + 11) returns 6

Sqr (-4) returns an error

### Numeric functions - Int

• Int (n) returns the greatest integer less than or equal to n

• requires exactly one integer input value

• n may be a numeric expression

• Examples: assume n is 10

Int (5.2) returns 5

Int (-6.7) returns -7

Int (n + 15) returns 25

### Numeric functions - Round

• How numbers are rounded to integers:

• 23.7 rounds up to 24

• 23.4 rounds down to 23

• 23.5 rounds up to 24

nRound (n)

1.3 1

1.7 2

-1.6-2

.2 0

### Another format for Round

• Round (2.357, 2) returns 2.36

• Round (1234.97899, 2) returns 1234.98

• This variation of Round is useful when our programs are processing monetary values.

• Example:

Private Sub Command1_Click()

Picture1.Print Round(txtNum.Text, 2)

End Sub

### Two mathematical operators that are useful in programs

• If x & y are integers, then the integer quotient of x divided by y can be found by using \

quotient = x \ y

• Also, to get the remainder, use mod:

remainder = x mod y

• try it with: x = 26; y = 7

### Numeric functions - Rnd

• Used to enable your program to generate pseudorandom values; useful in the creation of games.

• Rnd does not require any input value and returns a numeric value r where 0 <= r < 1

Int (Rnd * 10)will generate

a value that is between 0 & 9

### Some uses of Rnd

• Randomly generate an integer between 1 & 10:

x = 1 + Int(10 * Rnd)

• Randomly generate a 0 or 1:

x = Int (2 * Rnd)

• Randomly generate evens between 0 & 98:

x = 2 * Int (50 * Rnd)

more...

### More uses of Rnd

• Randomly generate

• a lowercase alphabetic character

• an uppercase alphabetic character

• the uppercase alphabetic characters between A & J

### Still more examples of Rnd

• Randomly generate an integer between

• 1 & 10

• 3 & 23

• 0 & 100 evens only

• 5 & 75 divisible by 5

• Randomly generate

• a lowercase alphabetic character

• an uppercase alphabetic character

• p. 132: #116, 117

### Lab

• Page 132 # 121

• Page 133 #122, 124