第4章 习题参考答案.doc

5第4章 程序设计的三种基本结构第4章 习题参考答案一、判断题题号12345678答案二、选择题题号12345答案ADBBB三、程序阅读写出下列各段程序执行后的输出结果。178578635786413578642 2 w=4、w=13、w=135、w=31 3此题有点错误，修改如下：是将语句“If k Asc(A) Then k = k + 26”改为： If k Asc(Z) And k Asc(a) Then k = k + 26 改后的答案： xyza12 uvw& 4ABBBCCCCCDDDDDDDEEEEEEEEE5此题的“IF KeyAsci=13 Then”改为“IF KeyAscii=13 Then” 答案是：129四、程序填空题1 (1) Sing=-1(2) For i=2 to 19(3) Sing=-Sing2 (1) Len(oldsen)(2) Mid(oldsen ,i,1)(3) Ucase(char)(4) char3(1) Len(str1)(2) Length-1(3) Mid(str1,i,2)(4) Sum=04(1) Trim(Str(i)(2) Trim(Str(i*i)(3) Right(x2,Len(x1)=x15.(1) last_one = last_two(2) last_two = this_one(3) i = i+1(4) i-1五、编程题1 Private Sub Form_Click() Dim R1 As Double, R2 As Double R1，R2 表示两电阻值 Dim Rp As Double, Rs As Double R1 = Val(InputBox(输入电阻R1=？) R2 = Val(InputBox(输入电阻R2=？) Rp = R1 * R2 / (R1 + R2) Rs = R1 + R2 Rp = Fix(Rp * 1000 + 0.5) / 1000 保留小数点后3位 Rs = Fix(Rs * 1000 + 0.5) / 1000 保留小数点后3位 MsgBox 并联电阻是： & Rp & vbCrLf & 串联电阻是： & RsEnd Sub2Private Sub Form_Click() Dim N As Long N = Val(InputBox(请输入年份, 提示框) If (N Mod 400 = 0) Or (N Mod 4 = 0 And N Mod 100 0) Then 判断条件 Print N & 年是闰年 Else Print N & 年不是闰年 End IfEnd Sub3Private Sub Form_Click() Dim a!, b!, c!, s!, x! a = Val(InputBox(Enter A=?) b = Val(InputBox(Enter B=?) c = Val(InputBox(Enter C=?) If a + b c And b + c a And a + c b Then 如果能构成三角形 x = (a + b + c) / 2 s = Sqr(x * (x - a) * (x - b) * (x - c) Print S=; s Else Print 数据有错,不能构成三角形 End IfEnd Sub4(此题不适合使用Select语句)Private Sub Command1_Click() Dim x As Double, fx As Double x = Val(InputBox(输入x=?) If x 0 And x -3 Then fx = x * x + x - 6 ElseIf x = 0 And x 10 And x 2 And x 3 Then fx = x * x - 5 * x + 6 Else fx = x * x - x - 1 End If Print x= ; x; f( & x & )=; fxEnd Sub5Dim i As Integer Dim s As Long, t As Long t = 1 For i = 1 To 10 t = t * i s = s + t Next i Print S= & s6Dim i%, s!, n!, t!, f% i = 1 项数 s = 0 累加和 n = 1 阶乘 t = 1 通项 f = 1 系数 Do While t 0.000001 s = s + f * t i = i + 1 n = n * i t = 1 / n f = -f 表示符号 Loop Print S=; s7方法一Private Sub Form_Click() Dim i As Integer Dim Hundred As Integer, Ten As Integer, One As Integer 定义百位，十位，个位数 For i = 100 To 999 Hundred = i 100 求百位数 Ten = (i 10) - Hundred * 10 求十位数 One = i Mod 10 求个位数 If i = Hundred 3 + Ten 3 + One 3 Then 判断是否为素数 Print i & 是水仙花数 End If Next iEnd Sub方法二Private Sub Form_Click() Dim i As Integer Dim Hundred As Integer, Ten As Integer, One As Integer 定义百位，十位，个位数 For Hundred = 1 To 9 百位数 For Ten = 0 To 9 十位数 For One = 0 To 9 i = Hundred * 100 + Ten * 10 + One If i = Hundred 3 + Ten 3 + One 3 Then 判断是否为素数 Print i & 是水仙花数 End If Next One Next Ten Next HundredEnd Sub8Dim a As Double, x0 As Double, x1 As Doublea = Val(InputBox(“输入a=?”)x0 = a 初值x1 = 2 / 3