Random Number generation

Question

What should be the approach to generate 10 unique numbers that should not match among a group of 10 people's generated answer ?

Answer 1

You could use OS facilities to generate a GUID (globally unique identifier).

A GUID is a 32-digit hexadecimal that looks like this: {21EC2020-3AEA-1069-A2DD-08002B30309D} (shamelessly stolen from the GUID wikipedia article). That makes it a 128 bit number. Now, it has all those annoying characters in the way, but there's nothing stopping you from removing the extraneous character and converting from hex and treating it as a plain number.

For practical reasons, you'll want to note that a 128-bit number is a bit unwieldy in some languages, such as C99. But you can still use compiler extensions (GCC has __uint128_t) or deal with it some other way.

Answer 2

This one has a nice solution. I'm assuming you have to give numbers 1-10 to 10 different people in a random way (but the principle also works if you have 10 (or more) different, non-consecutive numbers).

• Arrange the numbers in an array.
• Use a shuffling algorithm to shuffle the elements in the array.
  • (Shuffling algorithms : http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle)
• Read the first 10 values from the array, assigning them to each of the ten people.