Write a code that checks a C program
for unbalanced parenthesis and square
and curly braces.  You program should
take a stream of C source code in and
print out either a message indicating
that everything is balanced or else
the line in which the first unbalanced
delimiter is noticed.  For example, 
passing in the code

int main()
{
  int a[] = { 1 , 2 , 3 ];
}

should print out
"Error on line 3"
since the square bracket does not match
the curly brace before it.

Remember that braces and parentheses can
be deeply nested in C, and
your code should work in a fairly general
setting.  You will probably find it
helpful to use a stack in your code.