Code for implementing table-driven address change access-scenario from code Daquan chapter 12th: complex data types

The following is the implementation of access without address change

// Inventory class <br/> public class stock {<br/> int stockid; // No., which must be 0-9999 <br/> string category; // Category <br/> string goodname; // product name <br/> int amount; // quantity <br/> Private Static stock [] stocks = new stock [10000]; // if the address change access method is not used, only one primary query table is stocks <br/> static {<br/> for (INT I = 0; I <stocks. length; I ++) {<br/> stocks [I] = new stock (); <br/>}< br/> public stock () {// empty constructor </P> <p >}< br/> public stock (INT stockid, S Tring category, string goodname, int amount) {<br/> // For the sake of simplicity, check whether the Number, category, product name, and quantity are legal. <br/>, assuming that the stockid of each newly added stock is not the same as the previous one <br/> This. stockid = stockid; <br/> This. category = category; <br/> This. goodname = goodname; <br/> This. amount = amount; <br/> stocks [stockid] = This; // you can directly access the corresponding inventory to stocks through stockid, in this way, you can directly query the specific inventory information through stockid <br/>}< br/> Public int getstockid () {<br/> return stockid; <br/>}< br/> Public void setstockid (INT stockid) {<br/> This. stockid = stockid; <br/>}< br/> Public String getcategory () {<br/> return category; <br/>}< br/> Public void setcategory (string category) {<br/> This. category = category; <br/>}< br/> Public String getgoodname () {<br/> return goodname; <br/>}< br/> Public void setgoodname (string goodname) {<br/> This. goodname = goodname; <br/>}< br/> Public int getamount () {<Br/> return amount; <br/>}< br/> Public void setamount (INT amount) {<br/> This. amount = amount; <br/>}< br/> Public static stock [] getstocks () {<br/> return stocks; <br/>}< br/> Public static void main (string [] ARGs) {<br/> stock [] stocks = stock. getstocks (); // get all inventories, no inventory currently <br/> system. out. println (stocks [0]); // The printed result is null <br/> // Add inventory to stocks <br/> stock stock1 = new stock (0, "Fruit", "app Le ", 100); // fruit classification, 100 cases for Apple <br/> stock stock2 = new stock (235," vegetable "," carrot ", 200 ); // vegetable classification, 200 cases of carrots <br/> stocks = stock. getstocks (); // obtain all existing inventory information </P> <p> system. out. println (); <br/> // obtain the inventory information from the primary query table based on the stockid, and print <br/> stock stock3 = stocks [1]; <br/> stock stock4 = stocks [235]; </P> <p> system. out. println ("stock3 inventory information:"); <br/> If (stock3 = NULL) {<br/> system. out. println ("no inventory corresponding to stock3! "); <Br/>}< br/> else {<br/> system. out. println ("inventory type:" + stock3.getcategory (); <br/> system. out. println ("inventory name:" + stock3.getgoodname (); <br/> system. out. println ("inventory quantity:" + stock3.getamount (); <br/>}</P> <p> system. out. println (); </P> <p> system. out. println ("stock4 inventory information:"); <br/> If (stock4 = NULL) {<br/> system. out. println ("no inventory corresponding to stock4! "); <Br/>}< br/> else {<br/> system. out. println ("inventory type:" + stock4.getcategory (); <br/> system. out. println ("inventory name:" + stock4.getgoodname (); <br/> system. out. println ("inventory quantity:" + stock4.getamount (); <br/>}< br/> 

 

Step-by-Step access:

 

/* <Br/> * ≥ 90% a <br/> * <90.0% B <br/> * <77.5% C: C between 65 and 77.5 <br/> * <65.0% D: D between 50 and 65 <br/> * <50.0% E: E under 50 <br/> */<br/> public class studentscore {<br /> Private Static final int maxgradelevel = 4; </P> <p> Private Static double [] rangelimits = new double [5]; // score limit <br/> Private Static char [] grades = new char [5]; // grade, including a, B, c, d, e, F <br/> static {<br/> rangelimits [0] = 50.0; <br/> grades [0] = 'E '; <br/> rangelimits [1] = 65.0; <br/> grades [1] = 'D'; <br/> rangelimits [2] = 77.5; <br/> grades [2] = 'C'; <br/> rangelimits [3] = 90.0; <br/> grades [3] = 'B '; <br/> rangelimits [4] = 100.0; <br/> grades [4] = 'a '; <br/>}</P> <p> // obtain the description character of the corresponding level based on the Student Score: [abcdef] <br/> Public static char getstudentgrade (Double score) {<br/> int level = 0; <br/> char grade = 'a'; <br/> while (grade = 'A' & level <maxgradelevel) {<br/> If (score <rangelimits [level]) {<br/> grade = grades [level]; <br/> system. out. println ("current level:" + grade + "/T level:" + level); <br/> break; <br/>}< br/> else {<br/> level ++; <br/>}</P> <p> return grade; <br/>}</P> <p> Public static void main (string [] ARGs) {<br/> system. out. println ("78 points student level:" + studentscore. getstudentgrade (78); <br/>}< br/>