【正文】 Visual Basic 運(yùn)行期間庫的錯(cuò)誤處理缺乏安全性 ,因此代碼運(yùn)行期 間出現(xiàn)的錯(cuò)誤所造成的后果會(huì)非常嚴(yán)重 應(yīng)用：如果系 統(tǒng)環(huán)境為客戶機(jī) /服務(wù)器模式下的大規(guī)模多用戶環(huán)境 ， 那么應(yīng)用程序 必須都能夠準(zhǔn)確地解決可能出現(xiàn)的系統(tǒng)錯(cuò)誤和失敗應(yīng)用程序強(qiáng)調(diào)資源使用 ,這里如何對內(nèi)存、網(wǎng)絡(luò)服務(wù)器資源進(jìn)行直接控制是首要的考慮因素應(yīng)用程序使用超大規(guī)模數(shù)據(jù)庫 ， 例如數(shù)據(jù)庫表可能包含幾萬或幾十萬條記錄 計(jì)算機(jī)系統(tǒng)中的任何軟件 ， 都是由大大小小的各 種軟件組成部分構(gòu)成 ， 各自按照特定的算法來實(shí)現(xiàn) ， 算法的好壞直接決定所實(shí)現(xiàn)軟件性能的優(yōu)劣。算法是一組有窮的規(guī)則，它們規(guī)定了解決某一特定類型問題的一系列運(yùn)算，是對解題方案的準(zhǔn)確與完整的描述。分析算法可以預(yù)測這一算法適合在什么樣的環(huán)境中有效地運(yùn)行，對解決同一問題的不同算法的有效性做出比較； ⑤ 驗(yàn)證算法。滿足前四個(gè)特性的一組規(guī)則不能稱為算法，只能稱為計(jì) 算過程，操作系統(tǒng)是計(jì)算過程的一個(gè)例子，操作系統(tǒng)用來管理計(jì)算機(jī)資源，控制作業(yè)的運(yùn)行，沒有作業(yè) 17 運(yùn)行時(shí)，計(jì)算過程并不停止，而是處于等待狀態(tài)。 另外，當(dāng)給定的問題已有多種算法時(shí)，選擇其中復(fù)雜性最低者，是在選用算法時(shí)應(yīng)遵循的一個(gè)重要準(zhǔn)則。算法在計(jì)算機(jī)上執(zhí)行運(yùn)算，需要一定的存儲(chǔ)空間存放 描述算法的程序和算法 所需的數(shù)據(jù)，計(jì)算機(jī)完成運(yùn)算任務(wù)需要一定的時(shí)間。要求算法中有待實(shí)現(xiàn)的運(yùn)算都是基本的，每種運(yùn)算至少在原理上能由人用紙和筆在有限的時(shí)間內(nèi)完成； ③ 輸入。描述算法的方法有多種形式，例如自然語言和算法語言，各自有 適用的環(huán)境和特點(diǎn)； ③ 確認(rèn)算法。算法是解題的步驟， 我們可以把算法定義成解一確定類問題的任意一種特殊的方法。 在使用 VB 進(jìn)行數(shù)據(jù)庫編程時(shí) ,通常 ,會(huì)首先選擇三種基本方法之一來進(jìn)行數(shù)據(jù)庫應(yīng)用程序的方案設(shè)計(jì) , 現(xiàn)在就將以上三種設(shè)計(jì)方法的適應(yīng)范圍及其優(yōu)缺點(diǎn)進(jìn)行一個(gè)比較。在打開一個(gè)工程（文件）時(shí)，該工程 有關(guān)的所有文件同時(shí)被裝載。 “代碼編輯器 ”窗口第 4 節(jié)用 Visual Basic 開發(fā)應(yīng)用程序使用 VB 編程，一般先設(shè)計(jì)應(yīng)用程 序的外觀，然后再分別編寫各對象事件的 程序代碼或其他處理程序，編程的工作要輕松多。不過在后期的 Basic 則改正了以上的缺點(diǎn)（如 Quick Basic），使得它也可以用來開發(fā)較大型的程序。一個(gè)工程一般由若干個(gè)窗體、標(biāo)準(zhǔn)模塊以及應(yīng)用環(huán)境組成。企業(yè)版允許專業(yè)人員以小組的形式來創(chuàng)建強(qiáng)大的分布式應(yīng)用程序。 “Visual”指的是采用可視化的開發(fā)圖形用戶界面（ GUI）的方法，一般不需要編寫大量代碼去描述界面元素的外觀和位置，而只要把需要的控件拖放到屏 幕上的相應(yīng)位置即可方便圖形設(shè)計(jì)圖形用戶界面； “Basic”指的是 BASIC 語言，因?yàn)? VB 是在原有的 BAISC 語言的基礎(chǔ)上發(fā)展起來的。 (2) How to calculate one to assign the algorithm the plexity. After finding solves a question the algorithm, is this algorithm realization, as for whether could find the method which realized, was decided in the algorithm circularity and the putation plexity, whether this question did have the solution algorithm, whether to provide the time resources which and the spatial resources the algorithm needed. 10 V i s u a l B a s i c 語言與算 法 1991 年，美國微軟公司推出了 Visual Basic(可簡稱 VB），目前的最新版本 是 VB 2020 Beta2(VB9)中文版。④ Parsing algorithm. The algorithmic analysis is requires how many puting time and the storage space to an algorithm makes the quota the analysis. The parsing algorithm may forecast that what environment this algorithm does suit in moves effectively, to solves the identical question different algorithm validity to make the parison。s window of code pursued shows add codes “code editing machine” window 4. Keep project One VB procedure one project, at the time of designing a application program, system will set up one be expanded and called. Project file of vbp, project file include all relevant information of file that project set up this, Keep project keep associated documents of project this at the same time. For example the window body produced when design interfaces is kept and being expanded and being called. From sum. In the window body of foxfire. At the time of opening a project( file), this project relevant files load at the same time. 5. Operate and debugged by procedure Operate the procedure thoroughpin operate selecting in the menu, when the mistake appears, VB system can offer information prompt can looked for and get rid of the mistake thoroughpin debug within operate menus too. 6 6. Can produce by executive program For make procedure can break away from VB environment, order to bee next life through file producing project of menu but executive program (eyeful). Can carry out this file directly after this. In produce, + executive program, and then through install guide bale all associated run independently after installation under the environment of windows 9 x/2020 as a software product. In puter system39。 Basic means BASIC language, because VB is developed on the basis of already existing BAISC language. VB is a kind of programming language in mon use of Microsoft, It, including VBA of the numerous Windows application software use VB language in Microsoft Excel, Microsoft Accessed. For users to carry on the secondary development。② Expresses the algorithm. The description algorithm39。⑤ Has poor. An algorithm always after carrying out had the poor step operation has terminated, namely this algorithm was may reach. Satisfies a first four characteristic group of rule not to be able to be called the algorithm, can only be called the putational process, the operating system is a putational process example, the operating system uses for to manage the puter resources, controls the manufacture industry movement, when has not made industry the movement, the putational process does not stop, but is at the waiting status. The algorithm plexity is the algorithm efficiency measure, when appraises the algorithm performance, the plexity is an important basis. The algorithm plex degree with moves puter resources how many which this algorithm needs related, needs the resources are more, indicated that this algorithm the plexity is higher。 Visual Basic 第 1節(jié) Visual Basic 的概述 Microsoft Visual B