Balanced Brackets and Parentheses.

Difficulty (2/5).

Many languages enclose expressions using brackets or parentheses of various kinds. For example, in Java, you might see expressions like the following:

s = new ArrayList<>();
A[(i*2)+1] = ((x+2)*(y-2));
public int getValue() { return val; }

Notice how in all of these cases there is a "balancing principle" that gives the brackets a hierarchical structure. The rules for this balancing are as follows:

1. Each open bracket must have a corresponding close bracket of the same kind to the right. Thus getValue() is balanced, but getValue(} is not.
2. A closing bracket must be the same kind as the nearest unclosed open bracket to the left. Thus, A[(i*2)+1] is balanced, but A[(i*2]) is not.

Write a program that will prompt the user for an input line and determine if it's brackets of various kinds are balanced. Support the following bracket types:

(), [], {}, <>

Test your program on the following expressions:

BALANCED:
(a+3)*(b+2)
{a[1], b[2], c[3]}
void alloc() { x = new ArrayList<>(b[3]); }
<<<< ((( [[ { x } ]] ))) >>>>

NOT BALANCED:
A[1) = 34;
(((( b )))
:) (:

Hint: Use a stack data structure.

CS1 Deadline: 12/6/2013
Use: handin cs1113 extra6 BalancedBrackets.java