ostringstream

[zhbcool]

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

	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

	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

[spoon!]

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

	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.

return "" + temp;

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

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

	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

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.

[dlorde]

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

[zhbcool]

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

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;
	}

}

[zhbcool]

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

[keang]

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

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

[zhbcool]

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