Question

I am new to iPhone programming. I have 10 number say (1,2,3,4,5,6,7,8,9,10). I want to choose randomly 1 number from the above 10 numbers. How can I choose a random number from a set of numbers?

Answer 1

If you simply want a value between 1 and 10, you can use the standard C rand() method. This returns an integer between zero and RAND_MAX.

To get a value between 0 and 9 you can use the % operator. So to get a value between 1 and 10 you can use:

rand()%10 + 1

If you don’t want the same series of pseudo random numbers each time, you’ll need to use srand to seed the random number generator. A good value to seed it with would be the current time.

If you’re asking about choosing a number from a list of arbitrary (and possibly non consecutive) numbers, you could use the following.

int numbers[] = {2,3,5,7,11,13,17,19,23,29};
int randomChoice = numbers[rand()%10];