getting same numbers when executing a random number generation method?

[auting82]

I am making a DAQ-Simulator that shall simulate generation of analog (0-1V) and digital 1 or 0 signals. When I call my method sampling () and display the sensor data in my textbox, I always get the same numbers for my Analog sensors. Since this is a Random generation it should have been different numbers every time I click on Sample button :sigh:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace DAQ_Simulator
{
public partial class Form1 : Form
{

    int counter;
    
    int maxSid = 10; //Number of sensors 7analog and 3 digital
    int maxAI, maxDI;
    // string sensor\_values;
    string sTxt;
    
    private DateTime datetime;
    // Create an array of 10 sensor objects
      Sensor\[\] sObj = new Sensor\[10\];
    

    public Form1()
    {
        InitializeComponent();
    }
    private void displaySensorData(object sender, EventArgs e)
    {     
    }
    private void groupSampl\_Enter(object sender, EventArgs e)
    {

    }
    private void textSampling\_TextChanged(object sender, EventArgs e)
    {
        


    }
    private void btnSampling\_Click(object sender, EventArgs e)
    {                  
            sampling();     
    }

    private void groupLogg\_Enter(object sender, EventArgs e)
    {

    }

    private void txtLogging\_TextChanged(object sender, EventArgs e)
    {

    }
    private void labelLoggingText\_Click(object sender, EventArgs e)
    {

    }
    private void btnLogging\_Click(object sender, EventArgs e)
    {
        
    }
    private void labelSensorValues\_Click(object sender, EventArgs e)
    {

    }
    private void textSensorValues\_TextChanged(object sender, EventArgs e)
    {
       
    }
    private void timer1\_Tick(object sender, EventArgs e)
    {
       
    }
    private void sampling()
    {
       

        for (counter = 0; counter < maxSid; counter++)
        {               
            sObj\[counter\] = new Sensor(counter);              
        }
        
        for (counter = 0; counter < maxSid; counter++)
        {

[Richard Deeming]

You're specifying the same seed each time, so you'll get the same sequence of pseudo-random numbers each time.

Random class : Retrieve the same sequence of random values[^]:

You can generate the same sequence of random numbers by providing the same seed value to the Random(Int32) constructor.

---

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[OriginalGriff]

Your Random instance is a local variable, which means you create a new one each time you call the GetDigitalValue method. Since the Random constructor begins the sequence with a seed value based on the computer clock, if you create several Random instances close together, it is very likely - particularly with modern fast computers - that the same seed value will be used, and as a result all teh instances will generate the same sequence. Change your Random instance to a private static variable, and you will get different results.

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay... AntiTwitter: @DalekDave is now a follower!

[Richard Deeming]

OriginalGriff wrote:

Since the Random constructor begins the sequence with a seed value based on the computer clock, ...

Except in the posted code, where each instance is passed a seed value. Either the index of the sensor, in the Sensor constructor; or 2 in the GetDigitalValue method. So it's no wonder they always return the same sequence of values. :laugh:

---

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer