LeaderElection.cpp

#include<mpi.h>
#include<iostream>
#include<vector>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include<unistd.h>
using namespace std;

int main()
{
	int myrank,nprocs,namelen;
	int initiator=0;
	char processorName[10];
 	MPI_Init(NULL,NULL);
 	MPI_Comm_size(MPI_COMM_WORLD,&nprocs);
 	MPI_Comm_rank(MPI_COMM_WORLD,&myrank);
	MPI_Get_processor_name(processorName, &namelen);

	//to find the maximum rank
	int max=0;

	// to initiate the random every time
//	srand(time(NULL));

	int *array = new int[nprocs];
//	int array[nprocs];

	for(int i=0;i<nprocs;++i)
	{
		array[i]=-1;
	}
	int root=0;
	if(myrank==0)
	{
		while(initiator==0)
		{
		srand(time(NULL));
		initiator=rand()%nprocs;
		}

		cout<<"The inititaor for all the processses will be "<<initiator<<endl;
	}


		MPI_Bcast(&initiator,1,MPI_INT,0,MPI_COMM_WORLD);


	if(myrank == initiator)
	{

		cout<<"\nThe initiator is(IN THE INITIATOR) "<<initiator<<endl;

		array[myrank] = myrank;

		//send to the process which is 1 bigger means make a ring
		MPI_Send(array,nprocs,MPI_INT,(myrank+1)%nprocs,999,MPI_COMM_WORLD);

		cout<<"\n\t\t"<<myrank <<" is waiting for the last process "<<(myrank-1)%nprocs<<" running on "<<processorName<<endl<<endl;
		MPI_Recv(array, nprocs, MPI_INT, (myrank-1)%nprocs, 999, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
		cout<<"\n\t\tThe initiator received the message \n"<<endl;

		cout <<"My rank is "<< myrank <<" running on "<<processorName<< endl<<endl;

		cout<<"The array in the rank "<<myrank<<" is"<<endl;
		for(int j=0;j<nprocs;++j)
			{
				cout<<array[j]<<" ";
			}
		cout<<endl; 
		max = 0;
		for(int i=0;i<nprocs;++i)
		{
			if(max<array[i])
				max = array[i];
		}


		cout<<"Winner is "<<max<<endl;
		//Broadcasting winner of the election

	}
	else if(myrank!=initiator){
		if(myrank == 0)
		{
		MPI_Recv(array, nprocs, MPI_INT, (nprocs-1)%nprocs, 999, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
		cout<<" My rank is "<<myrank<<" and I have received from "<<(nprocs-1)%nprocs<<" running on "<<processorName<<endl;
		}
		else
		{
		MPI_Recv(array, nprocs, MPI_INT, (myrank-1)%nprocs, 999, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
		cout<<" My rank is "<<myrank<<" and I have received from "<<(myrank-1)%nprocs<<" running on "<<processorName<<endl;
		}		


		cout<<"The array in the rank "<<myrank<<" is"<<endl;
		for(int i=0;i<nprocs;++i)
		{
			cout << array[i] << " ";
		}


		sleep(1);
		srand(time(NULL));
		int random= rand()%2+1;
		//cout << "\nRandom value is : " << random << endl;
		//Means he wants to participitate 2 or yes and 1 for no 
		if(random==2)
			array[myrank] = myrank;
		cout<<"\nSending array to the rank "<<(myrank+1)%nprocs<<endl<<endl;

		MPI_Send(array,nprocs,MPI_INT,(myrank+1)%nprocs,999,MPI_COMM_WORLD);


	}

		MPI_Bcast(&max,1,MPI_INT,max,MPI_COMM_WORLD);
		cout<<myrank<<" received thank you from winner \n";




	MPI_Finalize();
}