The rupee gained by 18 paise to 45 rupees 10 paise a dollar.Forex experts attributed it to banks and exporters preferring to reduce their position in view of sustained capital inflow from foreign funds into stock market.At the Interbank Foreign Exchange (Forex) market, the domestic unit opened higher at 45 rupees 16 paise a dollar from its last close of 45.29 rupees and moved in a range of 45.10 and 45.17 inthe early trade.