VB资料之家 计算机二级考试一扫空 (36) - 百度文库

ѭṹѭṹ

ص㣺

1յ֧˫֧Լ֧ṹĸʽԼƷ 2do-loopѭ估ѭṹij 3For-Nextѭ估ѭṹij 4ѭǶ

1 for-next ѭ䣺P69

һʽ for v=e1 to e2 [step e3]

[exit for]

ѭ

next v

Уv ѭƱӦΪ ͡ e1ѭƱijֵ

e2ѭƱֵ e3ѭƱIJֵ

ܣִй̣P70 ʹ˵ ֵ e3 >0 ʱָ v>e2, e3<0 ʱָv

ѭļ㹫ʽѭ=Int((e2-e1)/e3)+1 step 1 ʱ˲ֿʡԡ ѭִе exit for ʱѭ䣬תnext

һȥִС

1.1

1+2+3+4+5

Private Sub Form_click()

Dim s As Integer, i As Integer s = 0

For i = 1 To 5

s = s + i Next i Print \End Sub

1*2*3*4

Private Sub Form_click()

Dim s As Integer, i As Integer s = 1

For i = 1 To 4 s = s * i Next I

Print \End Sub

P70

P71

ȿlenmidʹã һַ A=abcd

1 len(A)=4 lenx ɻxַȡ(һΪ2ַ) 2 mid(x,n1,n2) :ȡӴ һȡӴ

mid(A,1,1)=a mid(A,1,2)=ab

mid(A,3,1)=c

һַһһȡַķ for I=1 to len(x) print mid(x,I,1) next I

ȡ

for I=len(x) to 1 step -1 print mid(x,I,1) next I

öıһַijЩַ mid(x,2,2)=k

1.2 ѭǶףP73

for I= 1 to 2 fot j=1 to 3

print Db next j print Da

next I P73

rnd(x): ʹ÷P73

ırnd(X)еXȡֵ۲

Private Sub Form_click() Print Rnd(1); Rnd(0) End Sub

[a,b]ΧĹʽP73

int((b-a+1)*rnd+a)

53λ For I=1 to 5

Print int((999-100+1)*rnd+100) Next I

ϰ P74

isNumeric(x) : жһַǷһִ xִֵΪTrue ִֵΪFalse

2 do-loop ѭṹP68

һʽ4 P68 do while e do

[exit do]

[exit do]

loop while e

loop

ʽһ

1жe ֵΪ true ִѭAΪfalse , ѭתloop һȥִС

2ѭִִloop䣬أ1

ͼP67 a

2.1 䣩

s=1+2+3+4+?? С55ʱ Private Sub Form_click()

Dim s As Integer, n As Integer s = 0

n = 0

Do While s < 55 n = n + 1 s = s + n Loop

Print s, n End Sub

ʽ

1ִѭ顣 2ִе loop while ʱж e ֵΪ true , ת1Ϊ false , ѭתloop һȥִС

ͼP67 (b)

ʽ

do until e

.. [exit do]

ʽģ do .

[exit do]

loop until e

loop ʽܣ

(1) жe ֵΪ false ִѭ䣻Ϊ true ѭתloop һȥִС

2ִloop ʱأ1 ͼP68 ͼ4-13 b

ʽĹܣ

1ִѭ

2ִloop ʱж e ֵΪ false , أ1Ϊ true , ѭתloop һȥִС ͼP68 ͼ4-13 a

ر˵ָʽסѭִе 1 while ֵΪ true ʱִѭ壬Ϊ false ʱѭ until ֵΪfalse ʱִѭ壬Ϊtrueʱѭ

P68 4-3

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