What‘s the difference between srand(1) and srand(0)

Question

I just found out the hard way that srand(1) resets the PRNG of C(++) to the state before any call to srand (as defined in the reference). However,

Answer 1

The srand() function uses the argument as a seed for a new sequence of pseudo-random numbers to be returned by subsequent calls to rand(). If srand() is then called with the same seed value, the sequence of pseudo-random numbers shall be repeated. If rand() is called before any calls to srand() are made, the same sequence shall be generated as when srand() is first called with a seed value of 1.

Maybe useful: http://pubs.opengroup.org/onlinepubs/009695399/functions/rand.html