after i exit the game suddently my iphone automatic switched off. i cannot switch it on but when i connected to the power sourch, it can switch on but no sim and cannot turn on the wifi.

After you plugged it in, what did it show as the battery charge level? Was the shutoff due to low battery charge?

Make sure you fully charge before trying to do anything with it. If it will not work right, do a reboot by holding both the power and home buttons until the apple logo appears and it restarts, ignoring the red slider if that appears. If it still will not work, take it to an Apple store genius bar for testing.