Make an ArrayList of expressions with grouping symbols and output whether the grouping symbols match. Test for ( ), [ ], { }, and < >. Type in the test data as shown in the sample run below. Use only the stack methods in java.util.Stack. Since the Java Collections classes always store objects, not primitives, you could process either a stack of Strings or of Characters. The shell below uses Strings.

that is our assignment

import java.util.*; public class ParenMatch { public static final String LEFT = "([{<"; public static final String RIGHT = ")]}>"; public static void main(String[] args) { System.out.println("Parentheses Match"); ArrayList parenExp = new ArrayList(); /* enter test cases here */ for( String s : parenExp ) { boolean good = checkParen(s); if(good) System.out.println(s + "\t good!"); else System.out.println(s + "\t BAD"); } } //returns the index of the left parentheses or -1 if is not public static int isLeftParen(String p) { return LEFT.indexOf(p); } //returns the index of the right parentheses or -1 if is not public static int isRightParen(String p) { return RIGHT.indexOf(p); } public static boolean checkParen(String exp) { } }

and this is the shell code we were given, I don't really understand the whol left paren right paren thing. Also paren here stands for parentheses.