VB解一元二次方程配方法源码

1、vb解一元二次方程配方法我也是一个vb的超级菜鸟，但是我运用我所学的数学知识，编辑了一个解一元二次方程的配方法过程的这么一个程序。我是自己原创，至于是不是首创就不知道了。(很多网上直接出答案的都是运用公式法计算的，那么我就想写个有过程的程序，完爆数学老师)好了，废话不说多，现在先上测试图，有图有真相嘛。这个程序有几个重点（后面源码都有注释）1、 a值要变为正数，否则将无法运行2、 开不尽的数要用根号表示，不会像2=1.414这么多小数3、 分母有理化，倒数第二步的分母不能为根号（标准）4、 移项时的符号注意变化。下面是界面介绍：下面直接上源码了，有注释自己可以理解。dim a$ ,b$,c$,

2、d$,e$,f$,g$,h$dim jj!dim ii!dim pp!private sub command1_click()a = text1.textb = text2.textc = text3.textd = text4.textif a = 1 then '第一步，先列出原式label3.caption = "x2"end ifif a = -1 thenlabel3.caption = "-x2"end ifif not a = 1 and not a = -1 thenlabel3.caption = a & "x

3、2"end ifif b > 0 thenlabel3.caption = label3.caption & "+" & belselabel3.caption = label3.caption & bend ifif c > 0 thenlabel3.caption = label3.caption & "x+" & c & "=" & delselabel3.caption = label3.caption & "x" &am

4、p; c & "=" & dend ifif a < 0 then '当a为负数时，每个项同时乘以-1a = -ab = -bc = -cd = -dend ifc = c - d '移项，将右边移向左边if a = 0 then '判断有无解label3.caption = label3.caption & vbcrlf & "原方程无解"end ifif (b 2) - (4 * a * c) < 0 thenlabel3.caption = label3.caption &

5、 vbcrlf & "原方程无解"end ifif a = 1 then '第二步，写出移项后的结果label3.caption = label3.caption & vbcrlf & "x2"end ifif a = -1 thenlabel3.caption = label3.caption & vbcrlf & "-x2"end ifif not a = 1 and not a = -1 thenlabel3.caption = label3.caption & vbcrl

6、f & a & "x2"end ifif b > 0 thenlabel3.caption = label3.caption & "+" & belselabel3.caption = label3.caption & bend ifif c > 0 thenlabel3.caption = label3.caption & "x+" & c & "=0"elselabel3.caption = label3.caption & &

7、quot;x" & c & "=0"end ife = (b 2) / (4 * a) '算出适合配方的新c值f = e - c '新c值与原c值的差，两边同时加差值if a = 1 then '第三步，写出初步配方的结果label3.caption = label3.caption & vbcrlf & "x2"end ifif a = -1 thenlabel3.caption = label3.caption & vbcrlf & "-x2"end

8、 ifif not a = 1 and not a = -1 thenlabel3.caption = label3.caption & vbcrlf & a & "x2"end ifif b > 0 thenlabel3.caption = label3.caption & "+" & belselabel3.caption = label3.caption & bend ifif e > 0 thenlabel3.caption = label3.caption & "x+

9、" & e & "=" & felselabel3.caption = label3.caption & "x" & e & "=" & fend ifg = (-b + sqr(b 2 - 4 * a * c) / (2 * a) '后台使用公式法计算h = (-b - sqr(b 2 - 4 * a * c) / (2 * a)if g > 0 and g < 1 then '给0 < y < 1的数前加个0g = "

10、;0" & gend ifif g < 0 and g > -1 theng = -gg = "-0" & gend ifif h > 0 and h < 1 thenh = "0" & hend ifif h < 0 and h > -1 thenh = -hh = "-0" & hend ifjj = sqr(a)if a = 1 then '第四步，运用完全平方公式进行配方label3.caption = label3.caption &

11、; vbcrlf & "（x"end ifif a = -1 thenlabel3.caption = label3.caption & vbcrlf & "（-x"end ifif not a = 1 and not a = -1 thenif not len(cstr(jj - fix(jj) > 4 thenlabel3.caption = label3.caption & vbcrlf & "（" & sqr(a) & "x"end ifif l

12、en(cstr(jj - fix(jj) > 4 then小数大于3位时用根号表示，不直接开方label3.caption = label3.caption & vbcrlf & "（" & a & "x"end ifend if'-第一层-ii = sqr(e)if b > 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "+" & sqr(e) &

13、; "）2=" & fend ifif len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "+" & "" & e & "）2=" & fend ifend ifif b < 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "-" &

14、 sqr(e) & "）2=" & fend ifif len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "-" & "" & e & "）2=" & fend ifend if'-第二层-if a = 1 then '第五步，两边同时开根号label3.caption = label3.caption & vbcrlf & "x&qu

15、ot;end ifif a = -1 thenlabel3.caption = label3.caption & vbcrlf & "-x"end ifif not a = 1 and not a = -1 thenif not len(cstr(jj - fix(jj) > 4 thenlabel3.caption = label3.caption & vbcrlf & "" & sqr(a) & "x"end ifif len(cstr(jj - fix(jj) > 4

16、thenlabel3.caption = label3.caption & vbcrlf & "" & a & "x"end ifend ifif b > 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "+" & sqr(e) & "="end ifif len(cstr(ii - fix(ii) > 4 thenlabel3.capt

17、ion = label3.caption & "+" & "" & e & "="end ifend ifif b < 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "-" & sqr(e) & "="end ifif len(cstr(ii - fix(ii) > 4 thenlabel3.caption = la

18、bel3.caption & "-" & "" & e & "="end ifend ifpp = sqr(f)if not len(cstr(pp - fix(pp) > 4 thenlabel3.caption = label3.caption & "±" & sqr(f)end ifif len(cstr(pp - fix(pp) > 4 thenlabel3.caption = label3.caption & "

19、77;" & fend iflabel3.caption = label3.caption & vbcrlf & "x=" '第六步，移项，x在左if len(cstr(jj - fix(jj) > 4 then '分母有理化(后补分母)label3.caption = label3.caption & "" & aend ifif a = 1 thenif not len(cstr(pp - fix(pp) > 4 thenlabel3.caption = label3.ca

20、ption & "±" & sqr(f)end ifif len(cstr(pp - fix(pp) > 4 thenlabel3.caption = label3.caption & "±" & fend ifif b > 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "-" & sqr(e)end ifif len(cstr(ii - fi

21、x(ii) > 4 thenlabel3.caption = label3.caption & "-" & "" & eend ifend ifif b < 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "+" & sqr(e)end ifif len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption

22、 & "+" & "" & eend ifend ifend if'-第一层-if not a = 1 thenif not len(cstr(pp - fix(pp) > 4 thenlabel3.caption = label3.caption & "（±" & sqr(f)end ifif len(cstr(pp - fix(pp) > 4 thenlabel3.caption = label3.caption & "（±"

23、; & fend ifif b > 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "-" & sqr(e) & "）/"end ifif len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "-" & "" & e & "）/"end

24、 ifend ifif b < 0 thenif not len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "+" & sqr(e) & "）/"end ifif len(cstr(ii - fix(ii) > 4 thenlabel3.caption = label3.caption & "+" & "" & e & "）/"end ifend

25、 ifif not len(cstr(jj - fix(jj) > 4 thenlabel3.caption = label3.caption & sqr(a)end ifif len(cstr(jj - fix(jj) > 4 thenlabel3.caption = label3.caption & aend ifend iflabel3.caption = label3.caption & vbcrlf & "x=" & g & "或x=" & h '第七步，得解end s

26、ubprivate sub command2_click()text1.text = ""text2.text = ""text3.text = ""text4.text = ""label3.caption = "解题区域"end subprivate sub command3_click()a = text1.textb = text2.textc = text3.textd = text4.textc = c - dlabel6.visible = truelabel7.visible =

27、 truelabel8.visible = truelabel9.visible = trueline1.visible = trueline2.visible = truelabel5.caption = "a=" & a & "，b=" & b & "，c=" & c '第一步，列出a、b、c的值（格式严谨）label5.caption = label5.caption & vbcrlf & "=b2-4ac=" & (b 2) - (4 * a * c) '第二步，算出变量b2-4ac的值if (b 2) - (4 * a * c) < 0 then '第三步，判断方程有无解label5.caption = label5.caption & vbcrlf & "b2-4ac < 0，方程无解。"elseif b > 0 thenlabel7.caption