one silly way is join them together.
but each of array's size is dynamic.
I hope find a way to implement it.
please see my pusedo code
publicvoid foo()// or public int[] foo()
{
int a[] =new a[500];
while(true){
...
while(case 1true){
a = ....// form array a, its size is over time.
// hope return a here for other methods
}
}
thanks
I'm not sure I understand your question.
Do you mean "Can you have multiple return statements?".
Then, yes!public int[] foo(Object arg) {
if (arg == null) {
return new int[1] {0};
}
return new int[3] {1, 2, 3};
}
Or, "Can I have multiple return values?".
Well, yes, sortof.
// Either
public void foo(int[] out1; int[] out2) {
out1[0] = 1;
out2[1] = 2;
}
//...
int[] a = new int[1];
int[] b = new int[1];
foo(a, b);
// now a[0] == 1 and b[0] == 2
// or more commonly
class Bar {
int[] first = new int[1];
int[] second = new int[1];
}
//...
public Bar foo() {
Bar result = new Bar();
result.first[0] = 1;
result.second[0] = 2;
}
//...
Bar bar = foo();
// now bar.first[0] == 1 and bar.second[0] == 2
> > > Can we have Multiple return statements
> >
> > Yes, but only one return statement's value will
> > actually be returned.
>
> and it's the first one encountered by your program as
> it flows through your method.
Not necessarily:
try {
return 1; // 1st return
}
finally {
return 2; // 2nd return
}
The above will return 2 (unless wrapped in another try statement whose finally returns something else).
Note that this is a horrible way to write code. You should never return, throw, break, or continue out of finally. I'm just pedantically, ballsniffingly countering the claim that it's the first return statement whose value is returned. So sue me.
:-)
nice reply, I really appreciate all of guys.
I still have a problem. PLease see my code.
int i = 0;
...
while(line=br.readLine() !=null)//parse a file
{
i++;
if(line=="hello")
{
...
while((line=br.readLine()) != null && ..)
{
i++;
int x = ..//assign x a value
}
return x;
}
}
I found that the cpu executes into infinity. When I track the i value,I found after return x then come back, i becomes 0 again, and String line begins from the first row of the file again.
Is the problem that after return x, it goes out of the method.Once it comes back, variables are refreshed by the memory?
sorry for my english.
yes, i used equals.
soory the question is return an array.
public int[] xxx() {
int i = 0;
...
while(line=br.readLine() !=null)//parse a file
{
i++;
if(line=="hello")
{
...
while((line=br.readLine()) != null && ..)
{
i++;
int x[] = ..//assign x array values by a for loop
}
return x;
}
}
}
I guess it is a return array to arise such a problem, how to treat it?
This
while((line=br.readLine()) != null && ..)
{
i++;
int x = ..//assign x a value
}
return x;
Is emitting a foul and unpleasant odor of which the only possible source is that you have an class variable of some description that is named x.
ok,cotton.please my whole code.
God bless you.
import java.io.*;
import java.util.List;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.regex.*;
import java.util.StringTokenizer;
public class ParseFile
{
private String Filename="test.txt";
private double x1, y1, x2, y2; // to plot lines from (x1,y1) to (x2,y2)
private double xy[]= new double[206];
public double[] xyforStroke()
{
// parse a file to read line by line;
File file = new File(Filename);
try
{
BufferedReader br = new
BufferedReader(new FileReader(Filename));
String line;
String s1 = "0.5 setlinewidth 0.0 setgray";
String s2 = "stroke clear";
String[] parts;
int iter = 0;
while ((line = br.readLine()) != null )
{
iter++;
System.out.printf("iterative at %d: ",iter);
line = line.trim();
System.out.println(line);
if (line.equals(s1)) //true
{
List<Double> xList = new ArrayList<Double>();
List<Double> yList = new ArrayList<Double>();
System.out.printf("iterative at %d: ",iter);
line = line.trim();
System.out.println(line);
while ((line = br.readLine()) != null && !line.equals(s2))
{
iter++;
System.out.printf("iterative at %d: ",iter);
line = line.trim();
System.out.println(line);
parts = line.split("\\s+");
xList.add(Double.parseDouble(parts[0]));
yList.add(Double.parseDouble(parts[1]));
}
Double[] x = xList.toArray(new Double[xList.size()]);
Double[] y = yList.toArray(new Double[yList.size()]);
System.out.println("Test in ParseFile.java");
for (int i = 0; i<xList.size();i++)
{
xy[i]= x[i].doubleValue();
xy[i+xList.size()] = y[i].doubleValue();
System.out.printf("%10.5f\n",xy[i]);
}
xy[xy.length-1] = xList.size();
// put non-zero x or y elements's size at the last element of array xy;
//setxy(xy); // pass array reference
System.out.printf("return first time when iter=%d\n",iter);
return xy;
}
//return xy;
}
}
catch (Exception exception) {
exception.printStackTrace();
}
System.out.printf("return null here");
return null;
}
>
the questions is I am going parse a txt file which has many same data structure sections.
I try to parse each section over time and return them for plotting.
However I only can get the first section return values then repeat forever.
The data file is
%!PS-Adobe-3.0 EPSF 3.0
%%BoundingBox: 0 0 612 792
%%Title: Developmental Testing
%%CreationDate: 06/07/2007 08:45:57
%%EndComments
/Helvetica findfont 9 scalefont setfont
0.5 setlinewidth 0.0 setgray
20.000020.0000 moveto
592.000020.0000 lineto /
592.0000 772.0000 lineto /
20.0000 772.0000 lineto /
20.000020.0000 lineto /
stroke clear
22.000022.0000 moveto
590.000022.0000 lineto /
590.0000 770.0000 lineto /
22.0000 770.0000 lineto /
22.000022.0000 lineto /
stroke clear
...
If I remove the return statement, I found that I can go through the entire data file, but how can I return each section data?
