No Duplication in the question

[carlosrowlett]

Hey guys,

I m making a program that selects questions from an array numbered 1-40. I put in a random functions so the questions are chosen randomly.

But i want to have it so that theirs no duplication in the questions like if the number is already chosen skip and pick the next.

Any help would be much appreciated.

[nucleon]

The usual approach here is to "shuffle" the numbers and then pick them off one by one. (Code untested.)

// Load array
for (int i = 0; i < 40; ++i)
    n[i] = i + 1;
// Shuffle
for (int i = 39; i > 0; --i) {
    // Pick rnd position and switch that element with i
    int r = rand() % (i + 1);
    int t = n[r]; n[r] = n[i]; n[i] = t;
}
// Use them in array order
for (int i = 0; i < 40; ++i)
    doWhatever (n[i]);