Dynamic Memory Allocation Which is best?

[GNiewerth]

Using std::vector solves that problem. When there´s an exception thrown in the array handling function there will be no cleanup. std::vector will clean up its memory because the vector variable goes out of scope when an exception occurs and its destructor will release the allocated memory. boost::scoped_array may be an alternative.

PS:
vector´s allocation overhead will be neglectible compared to reading a file from disk. Just make sure you don´t have to reallocate multiple times. Resizing the vector to the file´s size before reading into the vector will do only one allocation.