Using Currency Exchange Helper class

static void SR_CEH_Example1(Args _args)
{
    CurrencyExchangeHelper currencyExchangeHelper;
    CurrencyCode transCurrency = 'EUR';
    AmountCur amountCur = 500.00;
    AmountMst amountMST;

    currencyExchangeHelper = CurrencyExchangeHelper::newExchangeDate(Ledger::current(), systemDateGet());
    amountMST = currencyExchangeHelper.calculateTransactionToAccounting(transCurrency, amountCur ,true);
    info(strFmt('%1',amountMST));
}