Why does rand() % 7 always return 0?

by

Well, this

int seed;
for(seed = 1; seed < 10; seed++) {
    srand(seed);
    printf("%4d %16d\n", seed, rand());
}

prints 

   1            16807
   2            33614
   3            50421
   4            67228
   5            84035
   6           100842
   7           117649
   8           134456
   9           151263

which makes me think that rand() = seed * 16807

Wikipedia article Linear congruential generator confirms that CarbonLib indeed uses Xn+1 = Xn * 16807 to generate random numbers.

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