Re: 100 Random Single Variable Linear Equations

A deliberately chosen seed of 0 gets overwritten?
 
How about (since you're expecting a number)
 
   if (SEED=="") SEED = 1
 
or (for good measure) the more general pattern for
an "uninitialized" variable 'var'
 
   if (var=="" && var==0) ...   # uninitialized
   else ...   # initialized (including "" and 0)
 
But is a seed of 1 "better" than a seed of 0 ?
Both create deterministic random number sequences.
 
Only srand() (i.e. without argument) creates a
time-depending quasi non-deterministic sequence.
 
My choice would probably be
 
   if (var=="" && var==0) srand()   # random start
   else srand(var)   # deterministic
 
to have both options.