Roulette Selection in Genetic Algorithms

Question

Can anyone provide some pseudo code for a roulette selection function? How would I implement this:

Answer 1

From the above answer, I got the following, which was clearer to me than the answer itself.

To give an example:

Random(sum) :: Random(12) Iterating through the population, we check the following: random < sum

Let us chose 7 as the random number.

Index   |   Fitness |   Sum |   7 < Sum
0       |   2   |   2       |   false
1       |   3   |   5       |   false
2       |   1   |   6       |   false
3       |   4   |   10      |   true
4       |   2   |   12      |   ...

Through this example, the most fit (Index 3) has the highest percentage of being chosen (33%); as the random number only has to land within 6->10, and it will be chosen.

    for (unsigned int i=0;i