How do I insert random integers into a list?

Barb Walton

12y1.3kVisual Basic .NET

Help. Struggling with trying to figure this out.

5 Replies

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Vulpes12y ago
Accepted answer
Try this:

using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
Random r = new Random();
var list = new List();

// add n distict integers between 0 and m inclusive
int n = 20;
int m = 99;
for(int i = 0; i < n; i++)
{
int num = r.Next(m + 1);
if (!list.Contains(num))
{
list.Add(num);
}
else
{
--i;
}
}

// print them out in sorted order;
list.Sort();
foreach(int i in list) Console.WriteLine(i);
Console.ReadKey();
}
}

0
Vulpes12y ago
OK but that will inevitably mean some duplication as you need to choose more numbers (30) than there are in the range (20).

Anyway, the code simplifies to this:

using System;
using System.Collections.Generic;

class Program
{
static void Main()
{
Random r = new Random();
var list = new List();

// add 30 integers between 1 and 20 inclusive
for(int i = 0; i < 30; i++)
{
int num = r.Next(1, 21); // 1 to 20 (excludes 21)
list.Add(num);
}

// print them out in sorted order;
list.Sort();
foreach(int i in list) Console.WriteLine(i);
Console.ReadKey();
}
}

0
Barb Walton12y ago
Appreciate the response. It doesn't work for me. I need to chose 30 random integers to a list from 1 to 20.
0
Munesh Sharma12y ago
http://stackoverflow.com/questions/17530306/getting-random-numbers-from-a-list-of-integers
0
Abhay Shanker12y ago
try with this

Random rand = new Random();
List result = new List();
HashSet check = new HashSet();
for (Int32 i = 0; i < 300; i++) {
int curValue = rand.Next(1, 100000);
while (check.Contains(curValue)) {
curValue = rand.Next(1, 100000);
}
result.Add(curValue);
check.Add(curValue);
}
0