C ++ random numbers

Question

Next: http://www.fredosaurus.com/notes-cpp/misc/random.html

It mentions that if we want to create a random number in a range 1-10, we can do the following:

r = (rand() % 10) + 1;

Why are we adding 1? Can you just explain how this process works?

And as for the initialization of the random number generator, he mentioned the following:

srand(time(0));

Can you explain this process? And what happens if we do not initialize at all?

Thank.

Answer 1

You add 1 because you need a random number of 1-10, not 0-9, which will be %without +1.

, 10 % 10 == 0 9 % 10 == 9, 0-9.
+1 "" 1-10- > 10 % 10 + 1 == 1 9 % 10 + 1 == 10

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Answer 2

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Answer 3

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Answer 4

1?

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Answer 5

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Answer 6

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Answer 7

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