實驗程序設計基礎

1、實驗 2程序設計基礎目的和要求(1) 掌握 VBNET常量、變量和表達式的定義和用法。(2) 熟練掌握 VB NET語句的書寫規(guī)范。(3) 掌握分支結構的用法。(4) 掌握循環(huán)結構的用法。(5) 掌握各種常用函數的用法。(6) 掌握數組的使用方法。內容和步驟求方程 ax2+bx+c=0 的解（參考課本 56 頁）求方程解的公式如下：方程的根有以下幾種可能：a=0，一個實根。b2-4ac=0 ，有兩個相等的實根。bZ-4ac0 ，有兩個不等的實根。b2-4ac 0 Thenre = -b / (2 * a)vi = Math.Sqrt(delta) / (2 * a) TextBox4.Text

2、 = Str(re + vi) TextBox5.Text = Str(re - vi)Elsere = -b / (2 * a)vi = Math.Sqrt(-delta) / (2 * a) TextBox4.Text = Str(re) & + & Str(vi) & i TextBox5.Text = Str(re) & - & Str(vi) & iEnd IfEnd IfEnd Sub篩選字母字符并反序存放。（參考課本57 頁 3.3.2 ）Public Class Form1Private Sub Button1_Click(ByVal sender As System.Obje

3、ct, ByVale As System.EventArgs) Handles Button1.ClickDim a, b, c As StringDim i As Integera = TextBox1.TextFor i = 1 To Len(a)IfUCase(Mid(a, i,1) = A And UCase(Mid(a, i,1) sunThenTextBox3.Text = TextBox3.Text +CStr (su(i) &,End IfNextHandles（五）編程實現如下兩種圖形的輸出*1. PrivateSub Button1_Click(ByVal sender A

4、s System.Object,Button1.ClickDim i, bAs IntegerFor i = 1To 5For b = 1To 5 - iTextBox1.Text = (TextBox1.Text & )Next bFor b = 1To 2 * i - 1TextBox1.Text = (TextBox1.Text & *)Next bTextBox1.Text = (TextBox1.Text & Chr(13) + Chr(10)Next iEnd SubEnd Class2. PublicClass Form1ByVal e As System.EventArgs)H

5、andlesPrivateSub TextBox1_TextChanged( ByVal sender As System.Object,ByVal e As System.EventArgs)End SubPrivateSub Button1_Click(ByVal sender As System.Object,Button1.ClickDim i, bAs IntegerFor i = 1To 5Ifi 3ThenFor b = 1To 3 - iTextBox1.Text = (TextBox1.Text & Next bFor b = 1To 2 * i - 1)ByVal e As System.EventArgs)HandlesTextBox1.Text = (TextBox1.Text & *)Next bTextBox1.Text = (TextBox1.Text & Chr(13) + Chr(10)ElseFor b = 1To i - 3TextBox1.Text = (TextBox1.Text & )Next bFor b = 1To 11 - (2 * i)TextBox1.Text = (TextBox1.Te