我有一个实现打印队列的程序。我有一个StackClass，可以找到stackjob和stackcycle，但是当我尝试打印这些值时，我会得到奇怪的结果，比如hashtags。我知道我需要覆盖toString()，但是当我添加额外代码时，我无法编译代码。
我无法在StackClass中添加代码，因为那里不存在stackjob和stackcycle。它们存在于PrintQueue文件中，这是我的主要方法文件。但是，我无法在main方法中添加代码，因为我收到此错误：PrintQ.java:10：';'期望的public String toString（）{^我无法在main方法之外添加代码，因为我得到：找不到stackjob和stackcycle的符号错误。我错过了什么吗？
我在我的Cycle类中为jobNumber和cycleNumber做了同样的事情并且它完美地工作：
@Override
public String toString()
{
StringBuilder sb = new StringBuilder();
sb.append(jobNumber + " ");
sb.append(cycleNumber);
return sb.toString();
}
下面，stackjob和stackcycle是我需要覆盖toString的值...任何建议？
StackClass<Integer> stackjob = new StackClass();
StackClass<Integer> stackcycle = new StackClass();
这是我的StackClass
public class StackClass<T> implements StackADT<T>
{
private int maxStackSize; //variable to store the
//maximum stack size
private int stackTop; //variable to point to
//the top of the stack
private T[] list; //array of reference variables
//Create an array of the size 100 to implement the stack.
//Postcondition: The variable list contains the base
// address of the array, stackTop = 0,
// and maxStackSize = 100.
public StackClass()
{
maxStackSize = 100;
stackTop = 0; //set stackTop to 0
list = (T[]) new Object[maxStackSize]; //create the array
}//end default constructor
//Constructor with a parameter
//Create an array of the size stackSize to implement the
//stack.
//Postcondition: The variable list contains the base
// address of the array, stackTop = 0,
// and maxStackSize = stackSize.
public StackClass(int stackSize)
{
if (stackSize <= 0)
{
System.err.println("The size of the array to "
+ "implement the stack must be "
+ "positive.");
System.err.println("Creating an array of the size 100.");
maxStackSize = 100;
}
else
maxStackSize = stackSize; //set the stack size to
//the value specified by
//the parameter stackSize
stackTop = 0; //set stackTop to 0
list = (T[]) new Object[maxStackSize]; //create the array
}//end constructor
//Method to initialize the stack to an empty state.
//Postcondition: stackTop = 0
public void initializeStack()
{
for (int i = 0; i < stackTop; i++)
list[i] = null;
stackTop = 0;
}//end initializeStack
//Method to determine whether the stack is empty.
//Postcondition: Returns true if the stack is empty;
// otherwise, returns false.
public boolean isEmptyStack()
{
return (stackTop == 0);
}//end isEmptyStack
//Method to determine whether the stack is full.
//Postcondition: Returns true if the stack is full;
// otherwise, returns false.
public boolean isFullStack()
{
return (stackTop == maxStackSize);
}//end isFullStack
//Method to add newItem to the stack.
//Precondition: The stack exists and is not full.
//Postcondition: The stack is changed and newItem
// is added to the top of stack.
// If the stack is full, the method
// throws StackOverflowException
public void push(T newItem) throws StackOverflowException
{
if (isFullStack())
throw new StackOverflowException();
list[stackTop] = newItem; //add newItem at the
//top of the stack
stackTop++; //increment stackTop
}//end push
//Method to return a reference to the top element of
//the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: If the stack is empty, the method
// throws StackUnderflowException;
// otherwise, a reference to the top
// element of the stack is returned.
public T peek() throws StackUnderflowException
{
if (isEmptyStack())
throw new StackUnderflowException();
return (T) list[stackTop - 1];
}//end peek
//Method to remove the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: The stack is changed and the top
// element is removed from the stack.
// If the stack is empty, the method
// throws StackUnderflowException
public void pop() throws StackUnderflowException
{
if (isEmptyStack())
throw new StackUnderflowException();
stackTop--; //decrement stackTop
list[stackTop] = null;
}//end pop
}
这是我的PrintQ：
import java.io.*;
import java.util.*;
public class PrintQ {
public static void main(String args[]) throws FileNotFoundException {
String job1;
int firstComma;
int secondComma;
QueueClass<Cycle> list= new QueueClass(100);
QueueClass<Integer> cyclelist= new QueueClass(100);
Cycle currentcycle= new Cycle();
Cycle priorityCycle= new Cycle();
Cycle Scycle= new Cycle();
try{
FileInputStream fstream = new FileInputStream("C:\\Users\\Whitney\\Desktop\\QueueIn.txt");
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
job1=br.readLine();
while ((strLine = br.readLine()) != null) {
switch(job1.charAt(0)) {
case 'q':
{
System.out.println("loop q");
firstComma=job1.indexOf(',');
secondComma=job1.lastIndexOf(',');
currentcycle.jobNumber=Integer.parseInt(job1.substring(firstComma+1,secondComma));
currentcycle.cycleNumber=Integer.parseInt(job1.substring(secondComma+1));
cyclelist.addQueue(currentcycle.cycleNumber);
list.addQueue(currentcycle);
while(currentcycle.cycleNumber > 0)
{
System.out.println(currentcycle.jobNumber + " " + currentcycle.cycleNumber);
currentcycle.cycleNumber--;
}
//list.print();
break;
}
case 'p':
{ System.out.println("loop priority");
firstComma=job1.indexOf(',');
secondComma=job1.lastIndexOf(',');
priorityCycle.jobNumber=Integer.parseInt(job1.substring(firstComma+1,secondComma));
priorityCycle.cycleNumber=Integer.parseInt(job1.substring(secondComma+1));
cyclelist.addQueue(priorityCycle.cycleNumber);
list.priorityinsert(priorityCycle);
while(priorityCycle.cycleNumber > 0)
{
System.out.println(priorityCycle.jobNumber + " " + priorityCycle.cycleNumber);
priorityCycle.cycleNumber--;
}
System.out.println(cyclelist);
//list.print();
break;
}
case 's':
{System.out.println("loop s");
firstComma=job1.indexOf(',');
Scycle.cycleNumber=Integer.parseInt(job1.substring(firstComma+1));
cyclelist.addQueue(Scycle.cycleNumber);
list.addQueue(Scycle);
while(Scycle.cycleNumber > 0)
{
System.out.println(Scycle.jobNumber + " " + Scycle.cycleNumber);
Scycle.cycleNumber--;
}
break;
}
case 'h':
{
System.out.println("loop halt");
StackClass<Integer> stackjob= new StackClass();
StackClass<Integer> stackcycle= new StackClass();
job1=(String) br.readLine();
//list.print();
System.out.println(stackjob.toString() +" " + stackcycle.toString());
while((strLine = br.readLine()) != null){
switch(job1.charAt(0)) {
case 'q':
{
firstComma=job1.indexOf(',');
secondComma=job1.lastIndexOf(',');
currentcycle.jobNumber=Integer.parseInt(job1.substring(firstComma+1,secondComma));
currentcycle.cycleNumber=Integer.parseInt(job1.substring(secondComma+1));
stackjob.push(currentcycle.jobNumber);
stackcycle.push(currentcycle.cycleNumber);
System.out.println("hi");
System.out.println(currentcycle.jobNumber + " " + currentcycle.cycleNumber);
//list.print();
break;
}
case 'p':
{
firstComma=job1.indexOf(',');
secondComma=job1.lastIndexOf(',');
priorityCycle.jobNumber=Integer.parseInt(job1.substring(firstComma+1,secondComma));
priorityCycle.cycleNumber=Integer.parseInt(job1.substring(secondComma+1));
stackjob.push(priorityCycle.jobNumber);
stackcycle.push(priorityCycle.cycleNumber);
System.out.println(priorityCycle.jobNumber-- + " " + priorityCycle.cycleNumber--);
break;
}
case 's':
{
firstComma=job1.indexOf(',');
secondComma=job1.lastIndexOf(',');
Scycle.cycleNumber=Integer.parseInt(job1.substring(secondComma+1));
stackjob.push(0);
stackcycle.push(Scycle.cycleNumber);
System.out.println(Scycle.jobNumber + " " + Scycle.cycleNumber);
break;
}
case 'h':
{
System.out.println("Halt - " + list);
continue;
}
}
job1=(String) br.readLine();
}
//System.out.println();
while((stackjob.isEmptyStack()==false) || (stackcycle.isEmptyStack()==false))
{
int printjob;
int printcycle;
Object peek;
printjob=stackjob.peek();
printcycle=stackcycle.peek();
stackcycle.pop();
stackjob.pop();
System.out.println("Job Number: "+printjob+" "+"Cycles Remaining: "+printcycle);
}
continue;
}
}
job1=br.readLine();
}
in.close();
}
catch (Exception e){//Catch exception if any
System.err.println("Error: " + e.getMessage());
}
Cycle whilecurrent= new Cycle();
while(list.isEmptyQueue()==false)
{
whilecurrent=list.front();
int whilecurrentcycle= cyclelist.front();
//list.print();
//System.out.println();
//while(whilecurrentcycle != 0)
//{
//System.out.println();//"loop "+whilecurrentcycle--);
//}
//System.out.println();
//System.out.println(whilecurrent);
cyclelist.deleteQueue();
list.deleteQueue();
}
list.print();
}
}
答案 0 :(得分：0)
循环遍历堆栈数组，构建一个字符串：
public String toString() {
StringBuilder output = new StringBuilder("[");
if ( stackTop > 0 ) {
for (int i = stackTop - 1; i >= 0; i--) {
if ( i == 0 ) {
output.append(list[i].toString());
}
else {
output.append(list[i].toString() + "|");
}
}
}
output.append("]");
return output.toString();
}
答案 1 :(得分：0)
如果你想要一个简短的解决方案，你总是可以返回列表的Arrays.toString（...）：
public String toString() {
return java.util.Arrays.toString(list);
}
否则只需遍历toString方法中的list数组，并将列表项返回的toString（）添加到StringBuilder中。