LinuxQuestions.org - Help With Modifying a Channel

Below is the program that I have downloaded, could anyone possibly show and tell me how to edit the first channel so that I can add an external mechanical-switch to the system instead of having to hit 'enter' on the keyboard?

To give some info as to what I am planning to do with the program... I'm testing the viscosity of liquids using LED's and Photosensors which are aligned on the side of a large bore capillary tube in order to catch the meniscus of the liquid as it passes. The passing of the meniscus should scatter the light from the LED and cause a change in the voltage across the gap which will be mapped by the program. As is right now, I have to hit enter to start the program when I flip the lever to start the flow of the liquid through the tube and would like to add a switch so I can set the sampling frequency, number of samples and number of channels the walk to the device and collect data.

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#include <stdlib.h>
#include <string>
#include <iostream>
#include <iomanip>
using namespace std;
#include "dataqsdk.h"

int main(int argc, char *argv[])
{
int MY_CHANNELS = atoi(argv[3]);
dataqsdk my_device; // device control/connection; main object
long int error_code = 0;
long int new_data = 0;
char *sn = 0; // serial number
int ChannelList[5] = {0,1,2,3,-1}; // used to set the channel list
int MethodList[5] = {0,0,0,0,0}; // used to set the method list
int points = 50; // how many scans to acquire
points = atoi(argv[2]); // convert to integer and use it instead
short int *iArray = new short int[points]; // will hold acquired data

cout << "Supported devices:" << endl;
char *temp = (char *)my_device.ProductName();
int i=0;
while(temp[i] != 0 && temp[i+1] != 0)
{
cout << &temp[i] << endl;
i += strlen(&temp[i]);
i++;
}
if(temp != 0)
{
delete [] temp;
temp = 0;
}

cout << "Setting product name: " << flush;
my_device.ProductName("DI-194RS"); // set
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << my_device.ProductName(); // get
cout << endl;

cout << "Setting device file &" << endl;
cout << "Connecting to device: " << flush;
// the device file is the one the device is connected to
// make sure the correct one is set
my_device.DeviceFile("/dev/ttyS0"); // set
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << my_device.DeviceFile(); // get
cout << endl;

cout << "Setting event point: " << flush;
my_device.EventPoint(1);
if(my_device.ControlError(error_code))
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << my_device.EventPoint();
cout << endl;

cout << "Setting channel count: " << flush;
// good idea to set this before channel list because it resets it
my_device.ADChannelCount(MY_CHANNELS); // set
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << my_device.ADChannelCount(); // get
cout << endl;

cout << "Setting channel list: ";
// make sure ChannelList is at least as big as ADChannelCount,
// this function uses ADChannelCount to determine how much of ChannelList
// to read and set up
my_device.ADChannelList(ChannelList); // set, doesn't have get
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << "Success";
cout << endl;

cout << "Setting method list: ";
// make sure MethodList is at least as big as ADChannelCount,
// this function uses ADChannelCount to determine how much of MethodList
// to read and set up
my_device.ADMethodList(MethodList); // set, doesn't have get
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << "Success";
cout << endl;

cout << "Setting sample rate: " << flush;
// it will automatically be set to max if the given value is bigger than
// or equal to the maximum value
my_device.SampleRate(atof(argv[1]));
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << my_device.SampleRate();
cout << endl;

cout << "Getting serial number: " << flush;
sn = (char *)my_device.InfoSerial(); // get
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << sn << endl;
if(sn != 0)
{
delete [] sn;
sn = 0;
}

cout << "Starting acquisition: " << flush;
my_device.Start();
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << "Acquiring..." << points << " scans" << endl;

cout << " A.C. 1\t A.C. 2\t A.C. 3\t A.C. 4\t\t\tDigital" << endl;

// gets one scan at a time and prints
// it to the screen immediately
int total = 0;
while(total <= points)
{
if(my_device.NewData(new_data))
{
for(int i=0; i<(new_data>points-total?points-total:new_data); i++)
{
my_device.GetDataEx(iArray, MY_CHANNELS);
if(my_device.ControlError(error_code))
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
{
// print out all the channels of the scan
for(int j=0; j<MY_CHANNELS; j++)
{
if(MY_CHANNELS == 5 && j == 4)
{
cout << "\t\t";
for(int xyz=0; xyz<3; xyz++)
cout << ((iArray[j] >> xyz) & 1);
}
else
{
cout.width(7);
cout.precision(2);
cout.setf(ios::fixed | ios::showpoint);
cout << (double)iArray[j]*10/32767 << ' ';
}
}
cout << endl;
}
}
total += new_data;
}
if(my_device.ControlError(error_code))
{
cerr << "Error: " << error_code << endl;
return 1;
}
}

if(iArray != 0)
{
delete [] iArray;
iArray = 0;
}

cout << "Stopping acquisition... " << flush;
my_device.Stop();
if(my_device.ControlError(error_code)) // error check
{
cerr << "Error: " << error_code << endl;
return 1;
}
else
cout << "Success" << endl;

return 0;
}