Fast-food giant McDonald's yesterday reported better than expected earnings in the second quarter but warned its future profits could be cut by the strong dollar and economic conditions overseas. Net earnings in the April to June period rose to $468.8 million (£339 million) from $438.2 million in second quarter 1997. Earnings per share were 66 cents, up from 61 cents in the 1997 quarter and beating Wall Street predictions by one cent. Sales in the quarter increased from $8.475 billion dollars to $9.247 billion.