ostringstream

so i have this code that i had used in c++, but i don't know what i should i use in java...

Code:

---

        public String getStringMessageID()
        {
                ostringstream temp;
                temp << messageId;
                return temp.str();
        }

---

These are the errors for the above:
ostringstream cannot be resolved to a type Assignment 10/src Messages.java line 114 1209617205928 8023
Syntax error on token "<<", invalid AssignmentOperator Assignment 10/src Messages.java line 115 1209617205929 8024


I also have another error which i dont know what to do about, but would love some help on

Code:

---

        static void sortArray(Message msg[], int size)
        {
                Message temp;
                boolean swapped = true;
                int count = 0;
                for(int index = 0; index < size && swapped; index ++)
                {
                        swapped = false;

                        for(int i = 0; i < (size - 1) - count; i ++)
                        {
                                if (msg[i].getDate() > msg[i + 1].getDate())
                                {
                                        swapped = true;
                                        temp = msg[i];
                                        msg[i] = msg[i + 1];
                                        msg[i + 1] = temp;
                                       
                                }
                        }count ++;
                }
        }

---

Here is the error i get for this one:
The operator > is undefined for the argument type(s) java.lang.String, java.lang.String Assignment 10/src Mailbox.java line 90 1209618068710 8102


If you would like to see the rest of the code just let me know and i will post it

Quote:

---

Originally Posted by zhbcool

so i have this code that i had used in c++, but i don't know what i should i use in java...

Code:

---

        public String getStringMessageID()
        {
                ostringstream temp;
                temp << messageId;
                return temp.str();
        }

---

These are the errors for the above:
ostringstream cannot be resolved to a type Assignment 10/src Messages.java line 114 1209617205928 8023
Syntax error on token "<<", invalid AssignmentOperator Assignment 10/src Messages.java line 115 1209617205929 8024

---

There is no way this "<<" stuff will work. But you can concatenate pretty much anything into a string.

Code:

---

return "" + temp;

---

You can also use StringBuffer if you need to do this a lot.

Quote:

---

Originally Posted by zhbcool

I also have another error which i dont know what to do about, but would love some help on

Code:

---

        static void sortArray(Message msg[], int size)
        {
                Message temp;
                boolean swapped = true;
                int count = 0;
                for(int index = 0; index < size && swapped; index ++)
                {
                        swapped = false;

                        for(int i = 0; i < (size - 1) - count; i ++)
                        {
                                if (msg[i].getDate() > msg[i + 1].getDate())
                                {
                                        swapped = true;
                                        temp = msg[i];
                                        msg[i] = msg[i + 1];
                                        msg[i + 1] = temp;
                                       
                                }
                        }count ++;
                }
        }

---

Here is the error i get for this one:
The operator > is undefined for the argument type(s) java.lang.String, java.lang.String Assignment 10/src Mailbox.java line 90 1209618068710 8102

---

You can do something like

Code:

---

firstString.compareTo(secondString) > 0

---

but I don't understand why you are comparing dates as strings (they won't order correctly as dates).

Also, you should not pass in a "size" argument, because the length of the array you can get with msg.length

Ideally, you should have your Message class implement Comparable, implement a compareTo() method, and use the Arrays.sort() function to sort your array or something.

Sun now recommend using StringBuilder rather than StringBuffer, unless it will be shared by multiple threads.

If you're planning to port code from C++ to Java, it would be worth reading up on the differences so you know about issues like these. Google turns up a number of articles - e.g. Differences Between Java and C++.

If you don't think carefully, you might believe that programming is just typing statements in a programming language...
W. Cunningham

I need to sort the messages by their date

maybe it will be easier to see the whole program at the point where the Sort comes in

Code:

---

import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class Mailbox {
       
        static int ID;
        static int count =0;
        Message A;
        static String a;
        static Message mes[];
       
public static void main (String args[]) throws IOException{
               
                File f = new File("messages");
                Scanner in = new Scanner(f);

                        System.out.print("Which messageID would you like to view? (ID)");
                        ID = (int) System.in.read();
                       
                       
                        while(count < 1000)
                        {
                               
                                in.nextLine();
                                mes[count].setDate(a);

                                in.nextLine();
                                mes[count].setSender(a);
                       
                                in.nextLine();
                                mes[count].setRecipient(a);
                       
                                in.nextLine();
                                mes[count].setBody(a);

                                count++;       
                        }
                        sortArray(mes, count);
                        if(IDSearch(mes, ID, count)==-1)
                                System.out.println("Error: Can't find your message");
                        else
                        {
                                System.out.println("Your message is:");
                                System.out.printf(mes[IDSearch(mes, ID, count)].toString());
                        }
                               
                        System.out.print(mes[0].toString());
                        System.out.print(mes[1].toString());
                        System.out.print(mes[2].toString());
                        System.out.print(mes[3].toString());
                        System.out.print(mes[4].toString());
                       

        return;
        }



/******************************************************************************
Name:                        sortArray
Description:        Function that sorts the array.  It a bubble sort algorithm
                                similar to the one you showed us in class.

Input:                       
                Message, integer
Output:                       
                none
******************************************************************************/
        static void sortArray(Message msg[], int size)
        {
                Message temp;
                boolean swapped = true;
                int count = 0;
                for(int index = 0; index < size && swapped; index ++)
                {
                        swapped = false;

                        for(int i = 0; i < (size - 1) - count; i ++)
                        {
                                if (msg[i].getDate() > msg[i + 1].getDate())
                                {
                                        swapped = true;
                                        temp = msg[i];
                                        msg[i] = msg[i + 1];
                                        msg[i + 1] = temp;
                                       
                                }
                        }count ++;
                }
        }


/******************************************************************************
Name:                        IDSearch
Description:        Function that searches the array to find position.  It then
                                returns position.

Input:                       
                Message, 2 integers
Output:                       
                integer                pos
        ******************************************************************************/
        static int IDSearch(Message msg[],int ID, int elements)
        {
                int pos = -1;

                for( int count  = 0; count < elements; count ++)
                {
                        if(msg[count].getMessageID() == ID)
                        {
                                pos = count;
                        }
                }

                return pos;
        }

}

---

I figured out the string thing i used:
string1.compareTo(string2) > 0;

Quote:

---

I figured out the string thing i used:
string1.compareTo(string2) > 0;

---

err how exactly does your solution differ from the one spoon! gave you? ie

Quote:

---

Originally Posted by spoon!

You can do something like
Code:
firstString.compareTo(secondString) > 0

---

It doesn't... i just wanted to re state the method so no one is confused on what method i was talkin about