本文藉著實際發展一電腦程式語言的語意診斷系統來說明使用物件導向程式設計的架構與技巧。本語意診斷系統置於個人電腦磁碟片中，可開機自動執行，並可由螢幕上看到畫面被劃分為程式區與回饋訊息顯示區，操作者可直接在程式區上，依所說明的操作方式，自由選擇完成下面兩是Quick BASIC程式設計的工作:一、用FOR-NEXT單迴圈設計於螢幕印出1+2+3...+100之和的程式。二、用FOR-NEXT雙迴圈設計於螢幕印出九九乘法表的程式。如產生語法或語意的錯誤，則系統會產生適當之回饋，並協助得到正確答案後再結束。 物件導向語言的基本理念是結合和處理這些的程式成為一個單元，這種單元叫做物件。一個物件函式(在C++此一物件導向程式語言中叫做成員函式，member function)通常提供唯一存取資料的管道。如果想讀取一個物件中的資料，得呼叫該個體的成員函式，它會讀取該項資料並回應其值。資料和它的函式稱為被包封(encapsulated)在一單一個體�堙A資料包封(data encapsulation)和資料隱蔽(data hiding)是描述物件導向語言的關鍵術語。物件導向語言中面對一個程式設計問題時，不會再問怎樣把問題分成一些函式，而是如何將它分成一些物件。而物件是類別的成員，經由類別就會產生繼承關係(inheritance)。00P的類別也可以分成次類別，在C++中具原始性質的類別叫作基本類別(base classes)，其它依此定義而擁有原始性質再加入自己特性的類別叫作衍生類別(derived classes)。基本類別包含一群衍生類別共同的部份，如同函式的功用，繼承關係簡化了物件導向程式，也釐清了程式各部份間的關係。物件導程式設計理念，將為未來程式設計發展的一重要方向。

　　　　　 The main purpose of his article is to analyze the construct and design technique of an object-oriented programming on which a computer semantic diagnostic system is relied. This semantic diagnostic system can be put in a floppy disk and automatically executed. After auto-execution, the computer screen is devided into two parts; the upper part is programming area and the lower part is the message feedback area. Users can write Quick BASIC computer programs freely under defined instructions. Two Quick BASIC programming exercises are designed to write and then run by the system; the first exercise uses FOR-NEXT loop to print out the summation from 1 to 100 and the second exercise uses double FOR-NEXT loop to print out the 9*9 multiplication table. If syntax or semantic errors occur, proper feedback message will help programmer to figure out errors until correct result is acquired. The basis of object-oriented programming is combining data and programs the process the data as unit. This unit is object. The member function provides the channel to retrieve data and return the value. Data encapsulation and data hiding are the key element to describe object-oriented programming language. While designing object-programs, the problem domains are analyzed by objects. Objects are members of class and the inheritance clarify their relationships and simplify the programs. Those idea point out an important direction of future programming design and more efforts are needed.