$_objectManager = MagentoFrameworkAppObjectManager::getInstance();
$currencyManager = $_objectManager->create('MagentoDirectoryModelCurrencyFac‌​tory')->create()->ge‌​tResource();
echo $currencySymbol = $currencyManager->getCurrencyCodeFromToCurrency($_code);

<?php
class Customclass{
    protected $storeManager;
    public function __construct(
        MagentoStoreModelStoreManagerInterface $storeManager
    ){
        $this->storeManager = $storeManager;
    }

    public function getStoreCurrency(){
        return $this->storeManager->getStore()->getCurrentCurrency()->getCurrencySymbol();
    }
}

$om = MagentoFrameworkAppObjectManager::getInstance();
 $currencyManager = $om->get('MagentoDirectoryModelCurrency');
 echo $currencyManager->getCurrencySymbol();

$priceHelper = $om->get('MagentoFrameworkPricingHelperData');
echo $priceHelper->currency($price, true, false);