我正在尝试使用数组在 StringInstrument 类中创建一个新对象。而不是StringInstrument ukulele = new StringInstrument(); 我把StringInstrument instrumentList[i] = new StringInstrument(); ; 但是，它一直给我错误“仅读取数组，从不写入”和“变量 instrumentList 已在方法 main(String[]) 中定义”。我无法弄清楚我做错了什么。我的代码如下所示。
class StringInstrument {//begin class
//declare variables
boolean isTuned;
boolean isPlaying;
boolean band;
public String nameOfInstrument;
int numberOfStrings;
String nameofStringsInInstrument[] = {"E", "A", "D", "G", "B"}; //an array of string names
public StringInstrument() {//begin contructor
numberOfStrings = 5;
isTuned = false;
isPlaying = false;
band = false;
}//end constructor
public int NumberOfStrings(int stringNumber){//begin method
System.out.println("The number of strings for the " + nameOfInstrument + " is " + stringNumber );
return this.numberOfStrings = stringNumber;
}//end method
public String InstrumentNameGet() {//begin method
return nameOfInstrument;
}//end method
public void SetInstrumentName (String instrumentName) {//begin getter method
nameOfInstrument = instrumentName;
}//end method
public String InstrumentNameDisplay() {//begin method
System.out.println("Your instrument is the " + nameOfInstrument);
return nameOfInstrument;
}//end method
public boolean PlayInstrument(){//begin method
System.out.println("You are playing your " + nameOfInstrument);
return isPlaying = true;
}//end method
public boolean TuneInstrument(){//begin method
System.out.println("Tune " + nameOfInstrument);
return isTuned = true;
}//end method
public boolean stopTuneInstrument() {//begin method
System.out.println("The" + nameOfInstrument + " is out of tune.");
return isTuned = false;
}//end method
public boolean StopPlayInstrument() {//begin method
System.out.println("The " + nameOfInstrument + " has stopped playing");
return isTuned = false;
}//end method
public boolean PlayInstrumentBand() {//begin method
System.out.println("The " + nameOfInstrument + " is playing in a band");
return band = true;
}//end method
public boolean StopPlayInstrumentBand() {//begin method
System.out.println("The " + nameOfInstrument + " has stoped playing with the band");
System.out.println("\n");
return band = false;
}//end method
}//end class
public class RandyGilmanP3 {//begin class
public static void main(String[] args) throws Exception{//begin main
java.io.File file = new java.io.File("RandyGilmanP3.txt");
//create a file
java.io.PrintWriter output = new java.io.PrintWriter(file);
//Declaring, creating, and intialize arrays
String[] instrumentList = new String [10];
String[] instrumentContent = new String [10];
int[] stringNumber = new int [10];
//input string names into array
instrumentList[0] = "Guitar";
instrumentList[1] = "Violin";
instrumentList[2] = "Bass Guitar";
instrumentList[3] = "Cello";
instrumentList[4] = "Banjo";
instrumentList[5] = "Sitar";
instrumentList[6] = "Rabab";
instrumentList[7] = "Viola";
instrumentList[8] = "Harp";
instrumentList[9] = "Ukulele";
//input string amounts into array
stringNumber[0] = 5;
stringNumber[1] = 4;
stringNumber[2] = 5;
stringNumber[3] = 4;
stringNumber[4] = 5;
stringNumber[5] = 18;
stringNumber[6] = 3;
stringNumber[7] = 4;
stringNumber[8] = 47;
stringNumber[9] = 4;
for (int i = 0; i < instrumentContent.length; i++){//begin for loop
StringInstrument instrumentList[i] = new StringInstrument();
output.println(instrumentList[i].InstrumentNameDisplay());
output.println(instrumentList[i].NumberOfStrings(stringNumber[i]));
output.println(instrumentList[i].TuneInstrument());
output.println(instrumentList[i].PlayInstrument());
output.println(instrumentList[i].PlayInstrumentBand());
output.println(instrumentList[i].StopPlayInstrument());
}//end for loop
}//end main
}//end class
I thought I would add the correct version, it took about 9 hours but I think I finally achieved the desired result.
class StringInstrument {//begin class
//declare variables
boolean isTuned;
boolean isPlaying;
boolean band;
public String nameOfInstrument;
int numberOfStrings;
String nameofStringsInInstrument[] = {"E", "A", "D", "G", "B"}; //an array of string names
public StringInstrument() {//begin contructor
numberOfStrings = 5;
isTuned = false;
isPlaying = false;
band = false;
}//end constructor
public int NumberOfStrings(int stringNumber){//begin method
System.out.println("The number of strings for the " + nameOfInstrument + " is " + stringNumber );
return numberOfStrings = stringNumber;
}//end method
public String InstrumentNameGet() {//begin method
return nameOfInstrument;
}//end method
public void SetInstrumentName (String instrumentName) {//begin getter method
nameOfInstrument = instrumentName;
}//end method
public String InstrumentNameDisplay() {//begin method
System.out.println("Your instrument is the " + nameOfInstrument);
return nameOfInstrument;
}//end method
public boolean PlayInstrument(){//begin method
System.out.println("You are playing your " + nameOfInstrument);
return isPlaying = true;
}//end method
public boolean TuneInstrument(){//begin method
System.out.println("Tune " + nameOfInstrument);
return isTuned = true;
}//end method
public boolean stopTuneInstrument() {//begin method
System.out.println("The" + nameOfInstrument + " is out of tune.");
return isTuned = false;
}//end method
public boolean StopPlayInstrument() {//begin method
System.out.println("The " + nameOfInstrument + " has stopped playing");
return isPlaying = false;
}//end method
public boolean PlayInstrumentBand() {//begin method
System.out.println("The " + nameOfInstrument + " is playing in a band");
return band = true;
}//end method
public boolean StopPlayInstrumentBand() {//begin method
System.out.println("The " + nameOfInstrument + " has stoped playing with the band");
System.out.println("\n");
return band = false;
}//end method
//Create an array of instrument objects
public static StringInstrument[] createInstrumentArray(){//begin method
StringInstrument[] instruments = new StringInstrument [10];
//Loop that inputs random integers into the array
for (int i = 0; i < instruments.length; i++){//begin loop
instruments[i] = new StringInstrument();
}//end loop
return instruments;
}//End method
public static void printInstrumentArray(StringInstrument[] instruments)throws Exception{
//request input from user
java.io.File file = new java.io.File("RandyGilmanP3.txt");
if(file.exists()){
System.out.println("FILE ALREADY EXIST");
System.exit(1);
}
//create a file
java.io.PrintWriter output = new java.io.PrintWriter(file);
String[] instrumentList = new String [10];
int[] stringNumber = new int [10];
//input string names into array
instrumentList[0] = "Guitar";
instrumentList[1] = "Violin";
instrumentList[2] = "Bass Guitar";
instrumentList[3] = "Cello";
instrumentList[4] = "Banjo";
instrumentList[5] = "Sitar";
instrumentList[6] = "Rabab";
instrumentList[7] = "Viola";
instrumentList[8] = "Harp";
instrumentList[9] = "Ukulele";
stringNumber[0] = 5;
stringNumber[1] = 4;
stringNumber[2] = 5;
stringNumber[3] = 4;
stringNumber[4] = 5;
stringNumber[5] = 18;
stringNumber[6] = 3;
stringNumber[7] = 4;
stringNumber[8] = 47;
stringNumber[9] = 4;
//Print an array of instruments and their actions
for (int i = 0; i < instruments.length; i++){//begin for loop
instruments[i].SetInstrumentName(instrumentList[i]);
output.println(instruments[i].InstrumentNameDisplay());
output.println(instruments[i].NumberOfStrings(stringNumber[i]));
output.println(instruments[i].TuneInstrument());
output.println(instruments[i].PlayInstrument());
output.println(instruments[i].PlayInstrumentBand());
output.println(" ");
}//end for loop
output.close();
}//end method
}//end class
public class RandyGilmanP3 {//begin class
public static void main(String[] args) throws Exception{//begin main
//declare instruments
StringInstrument[] instruments;
//create instrument array
instruments = StringInstrument.createInstrumentArray();
//Print instrument array
StringInstrument.printInstrumentArray(instruments);
}//end main
}//end class