Generate random float between two floats

I know this is a rather simple question, but I'm just not too good at maths.

I know how to generate a random float between 0 and 1:

float random = ((float) rand()) / (float) RAND_MAX;

• But what, if I want a function that given a range of two floats, returns a pseudorandom float in that range?

Example:

RandomFloat( 0.78, 4.5 ); //Could return 2.4124, 0.99, 4.1, etc.