Hello, I'm trying to write a program that evaluates a postfix expression using the vector class. I have done this successfully using stacks but I am experiencing trouble with vectors.
Here is the error message I am recieving:

I:\vector.java:26: type Vector does not take parameters
public static int evalPostfix(String str, Vector<Object> opndVect)
^
I:\vector.java:79: type Vector does not take parameters
Vector<Object> myvect = new Vector<Object>();
^
I:\vector.java:79: type Vector does not take parameters
Vector<Object> myvect = new Vector<Object>();
^
3 errors

Process completed.

Here is my code:

import java.util.*;
public class vector 
{
public static int convert(char chValue)
{
	switch(chValue)
	{
		case '0': return 0;
		case '1': return 1;
		case '2': return 2;
		case '3': return 3;
		case '4': return 4;
		case '5': return 5;
		case '6': return 6;
		case '7': return 7;
		case '8': return 8;
		case '9': return 9;
		default:
		{
			System.out.println("Error in evaluation");
			return -1;
		}//terminates default
	}//terminates switch
}//terminates text of convert method
//begin coding for evalPostfix method
public static int evalPostfix(String str, Vector<Object> opndVect)
{
	for(int index=0; index<str.length(); ++index)
	{
		//if current char is an integer
		char chValue=str.charAt(index);
		if('0'<=chValue && chValue<='9')
			//add the converted integer digit to the operand vector
		opndVect.add(convert(chValue));
		else
		{
			int opnd1=opndVect.get(opndVect.lastElement());
			opndVect.remove(opndVect.lastElement());
			int opnd2=opndVect.get(opndVect.lastElement());
			opndVect.remove(opndVect.lastElement());
			switch(chValue)
			{
				case '+':
				{
					int value=opnd1+opnd2;
					opndVect.add(value);
					break;
				}//end case +
				case '*':
				{
					int value=opnd1*opnd2;
					opndVect.add(value);
					break;
				}//end case *
				case '-':
				{
					int value=opnd1-opnd2;
					opndVect.add(value);
					break;
				}//end case -
				case '/':
				{
					int value=opnd1/opnd2;
					opndVect.add(value);
					break;
				}//end case /
			}//terminates switch 
		}//terminates else
		System.out.println("Top of vector is now: " + opndVect.get(opndVect.lastElement()));
	}//terminates for loop
	System.out.println("Evaluation: " + opndVect.get(opndVect.lastElement()));
	int result=opndVect.get(opndVect.lastElement());
	opndVect.remove(opndVect.lastElement());
	return result;
}//terminates evalPostfix method
//begin coding of main method
public static void main(String[]args)
{
	Vector<Object> myvect = new Vector<Object>();
	System.out.println("Enter a string in postfix notation");
	Scanner scan = new Scanner(System.in);
	String str="";
	str=scan.next();
	evalPostfix(str, myvect);
}//terminates text of main method
}//terminates text of vector class

When I remnove the <Object> parameters from the constructor call I recieve this message:
I:\vector.java:26: type Vector does not take parameters
public static int evalPostfix(String str, Vector<Object> opndVect)
^
I:\vector.java:79: Vector is abstract; cannot be instantiated
Vector myvect = new Vector();
^
2 errors

Process completed.

Thanks in advance for any help.

Are you compiling against java 1.5 or later? Those declarations of Vector are perfectly valid post-1.5. You have other issues with using get(Object) calls that are not valid, but the declarations are fine.

Comments
Thanks for the help.

I am using Java 5.0.

You have other issues with using get(Object) calls that are not valid, but the declarations are fine.

Can you be more specific about my other issues? Thanks.

This call opndVect.get(opndVect.lastElement()); isn't valid because lastElement() returns an Object and get() requires an int index parameter. lastElement() itself returns the last element in that Vector, so really the get() is redundant anyway.

If you're using 5.0, then do you have a version of that class named "Vector" (in caps, not lower case) in that directory? Because, as James mentioned, you may have namespace collision problems.

Wow! I turns out he was right! I had a Vector.class file in the same directory. Deleting that solved the problem. Thanks again to both of you for the help.

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