Single Layer Perceptron Learning Algorithm in C++

main.cpp

/*
 Perceptron Leanrning Algorithm
 By Tanmay Chakrabarty
 
 Compiled and Ran succesfully with C++ compiler @https://www.onlinegdb.com/
*/
#include<iostream>

using namespace std;

int
main() {

  double weights[4], Threshold = 0.5, sum = 0.0, output = 0.0;

  int values[16][4], given_value[4], i, j, k;

  char
  const * new_start = "Not Required";

  char option;

  /*
	 weights for storing the weights | Threshold to store the threshold
	 sum to store the weighted sum | output to store the 0 or 1 after comparing the sum with the threshold
	 values to store the values | given_value is the value that will entered by the user to test
	 i, j, k are loop controller | new_start is an indicator whether to start from the beginning or not while weights have been found ok for one of the 16 values
	 option has been used to take input from the user for program flow control
   */
  //(calculating and storing the values for the values)
  i = 0;

  j = 0;

  while (i < 16)

  {

	  j = 3;

	  k = i;

	  while (j >= 0)

	  {

		  values[i][j] = k % 2;

		  k = k / 2;

		  j--;

	  }

	  i++;

  }

  //starting the main loop
  option = 's';

  while (option == 's' || option == 'S')

  {

	  cout <<
		  "No kind of input error has been handled, enter accuret values\n";

	  cout << "Please input the weights:\n";

	  j = 0;

	  while (j < 4)

	  {

		  cout << "\tWeights 0" << (j+1) << ": ";

		  cin >> weights[j]; //taking the weights from the user
		  j++;

	  }

	  cout << "Please input the Threshold : ";

	  cin >> Threshold; //taking threshold from the user
	  i = 0;

	  while (i < 16) //to run the loop 16 times (0-15)
	  {

		  sum = 0;

		  j = 0;

		  while (j < 4)

		  {

			  sum += (values[i][j] * weights[j]); //calculating the weighted sum
			  j++;

		  }

		  if (sum < Threshold) //comparing weighted sum with threshold
			  output = 0; //and setting the value for the output
		  else

			  output = 1;

		  if (i < 8) //to find which class the value is from, it indicates that this is from class A (0-7)
		  {

			  if (output != 0) //The desired output of class A is 0, but if not then we will decrease
			  { //that corresponding weight of the input
				  j = 0;

				  while (j < 4)

				  { //multiplying with corresponding values beacuse we need to
					  weights[j] -= ((0.1) * (values[i][j])); //that weight which correspondingly having 1 in its input
					  j++; //if value is 0, "((0.1) * (values[i][j]))" will result 0
				  } //thus the weight will not decrease, otherwise, it will
				  new_start = "Required"; //as wrong weights has been found, thus after we have decreased the weigths
				  i = i; //we will test these weights for these inputs again and after ok, this value of
			  } //new_start will indicate to start from first value with these new corrected weights
			  else

			  {

				  if (new_start == "Required") //when weights has been found ok and new_start = "Required", it means we will start from first
				  {

					  new_start = "Not Required"; //Untill we found these weight faulty for any value we will just go on
					  i = 0;

				  } else

					  i++; //weights are ok, so go on
			  }

		  } else //this is class B part and same as previous, only that we will increase weights here
		  {

			  if (output == 1)

			  {

				  if (new_start == "Required")

				  {

					  new_start = "Not Required";

					  i = 0;

				  } else

					  i++;

			  } else

			  {

				  j = 0;

				  while (j < 4)

				  {

					  weights[j] += ((0.1) * (values[i][j]));

					  j++;

				  }

				  new_start = "Required";

				  i = i;

			  }

		  }

	  }

	  cout << "\nWeights are " << weights[0] << " , " << weights[1] <<
		  " , " <<
		  weights[2] << " , " << weights[3] << " while threshold is " <<
		  Threshold << "\n";

	  cout <<
		  "\nWeights are set, ready to percept\n";

	  option = 'e';

	  while (option == 'e'
		  or option == 'E')

	  {

		  cout <<

			  "\nPlease enter an element to find which class is it of : \t";

		  j = 0;

		  while (j < 4)

		  {

			  cin >> given_value[j]; //taking the value to test from user
			  cout << "\t\t\t\t\t\t\t";

			  j++;

		  }

		  sum = 0;

		  j = 0;

		  while (j < 4)

		  {

			  sum += (given_value[j] * weights[j]); //getting the weight
			  j++;

		  }

		  if (sum < Threshold) //comparing the weight with the threshold and getting the result
			  cout << "\nThe percepted element " << given_value[0] <<

			  given_value[1] << given_value[2] << given_value[3] <<

			  " is from Class A\n";

		  else

			  cout << "\nThe percepted element " << given_value[0] <<

			  given_value[1] << given_value[2] << given_value[3] <<

			  " is from Class B\n";

		  cout << "\nPress "
		  ""
		  "e"
		  ""
		  " to enter an element again or "
		  ""
		  "s"
		  ""
		  " to start from the beginning, any (else key+enter) to exit: ";

		  cin >> option;

		  if (option != 'e' || option != 'E' || option != 's' ||
			  option != 'S')

			  return 0;

	  }

  }

  return 0;

}