# peek method

E peek()

Returns the top element of the stack without removing it.

Throws NoGuaranteeException if the stack is empty.

Example:

    final stack = Stack<int>();
    stack.push(100);
    print(stack.peek()); // 100
    print(stack.length); // 1 (element still in stack)

## Implementation

    E peek() {
      if (empty()) {
        throw InvalidArgumentException('Stack is empty');
      }
      return _elements.last;
    }