How to randomise the elements of an array in C

Question

Okay, I'm writing a C program for a tennis tournament and I need a way to randomly select one of the elements from the array to play against another.

so basically i need something like: char contestant(rand) v char contestant (rand)

instead of just contestant(1) v contestant(2)

You should look up shuffling algorithms. There are several posts about them here on SO. — AntonH, Nov 17 '14 at 19:12
possible duplicate of [How to use rand function to](http://stackoverflow.com/questions/4270382/how-to-use-rand-function-to) — 2501, Nov 17 '14 at 19:12
Just google "c random element from array". This is a pretty common operation. — AtlasMeh-ed, Nov 17 '14 at 19:15

score 1 · Answer 1 · answered Nov 17 '14 at 19:15

1

If you mean you need 2 random indices from set of N but not same 2:

int c1 = rand()%N;
int c2 = (c1+1+rand()%(N-1))%N;

answered Nov 17 '14 at 19:15

Anonymous

Don't forget to use srand(unsigned int) before using rand(). – Venkatesh Nov 17 '14 at 19:30
Also nottice that c1 and c2 are in range from 0 to N-1 :) – Anonymous Nov 17 '14 at 19:34

1 Answers1