Code example for Stack

Methods: clear, push

0
		} 
	} 
 
	private void doOpChar(char op) {
		if (isInEquals) {
			stack.clear();
			isInEquals = false;
		} 
		stack.push(result);
		doLastOp(); 
		lastOp = op;
		tvOp.setText(String.valueOf(lastOp));
	} 
 
	private void doLastOp() { 
		isRestart = true;
		if (lastOp == '\0' || stack.size() == 1) {
			return; 
		} 
 
		String valTwo = stack.pop();