C# windows form application-PLEASEE HELLLPPP!!!

Question

need help on making a windows form application with a numericupdown and listbox button on it. when I enter 2 in numericupdown button, it should write

1,2

2,1

in listbox.

or when I enter 3 in numericupdown, it should create

1,2,3
1,3,2
2,1,3
2,3,1
3,1,2
3,2,1

it is like a binary tree, creating all possible options. please help!!!

Vulpes · Answer

Here's a version which uses a recursive algorithm to generate the permutations. Again I wouldn't use a maximum value of more than 8 for the NumericUpDown: private List GetPermsRecursive(int n) { if (n List perms = new List (); int[] a = new int[n]; Visit(a n 0 -1 perms); // call to recursive method return perms; } private void Visit(int[] a int n int k int level List perms) { level++; a[k] = level; if (level == n) { perms.Add(DisplayPerm(a)); } else { for (int i = 0; i { if (a[i] == 0) Visit(a n i level perms); } } level--; a[k] = 0; } private string DisplayPerm(int[] a) { var sb = new System.Text.StringBuilder(); for (int i = 0; i { sb.Append(a[i].ToString()); if (i } return sb.ToString(); } private void numericUpDown1_ValueChanged(object sender EventArgs e) { int n = (int)numericUpDown1.Value; listBox1.DataSource = GetPermsRecursive(n); }

Vulpes · Answer

Try the following which uses the QuickPerm algorithm (I've translated it from C to C#) to calculate all permutations of the numbers 12 .. n: http://www.freewebs.com/permute/quickperm.html I'd keep the maximum value of the NumericUpDown control to a fairly low value (say 8) otherwise it will take a long time to compute all the permutations: private List QuickPerm(int n) { if (n List perms = new List (); int[] a = new int[n]; int[] p = new int[n]; // all zero by default int i j tmp; for (i = 0; i perms.Add(DisplayPerm(a)); i = 1; while (i { if (p[i] { j = i % 2 * p[i]; tmp = a[j]; a[j] = a[i]; a[i] = tmp; perms.Add(DisplayPerm(a)); p[i]++; i = 1; } else { p[i] = 0; i++; } } return perms; } private string DisplayPerm(int[] a) { var sb = new System.Text.StringBuilder(); for (int i = 0; i { sb.Append(a[i].ToString()); if (i } return sb.ToString(); } private void numericUpDown1_ValueChanged(object sender EventArgs e) { int n = (int)numericUpDown1.Value; listBox1.DataSource = QuickPerm(n); }

musa demirtas · Answer

how can I use recursive method to do the same thing???