Program to solve knapsack problem using backtracking problem

// program to solve knapsack problem using backtracking problem

#include<iostream.h>
#include<conio.h>

class knapsack
{
	private:
		int p[20],w[20],m,x[20],y[20],n;
		int Bound(int,int,int);
		int fp,fw;

	public:
		knapsack()
		{
			fp=0;
		}
		void BKnap(int,int,int);
		void setdata();
		void getdata();
};

void knapsack::setdata()
{
	int i;

	cout<<"\nEnter number of elements: ";
	cin>>n;

	cout<<"\nEnter elements in the descending order of P/W\n";

	for(i=1;i<=n;i++)
	{
		cout<<"\nEnter profit of "<<i<<" element: ";
		cin>>p[i];
		cout<<"\nEnter weight of "<<i<<" element: ";
		cin>>w[i];
	}

	cout<<"\nEnter capcity of kanpsack: ";
	cin>>m;
}

int knapsack::Bound(int cp,int cw,int k)
{
	int b,c,i;

	b=cp;
	c=cw;

	for(i=k+1;i<=n;i++)
	{
		c=c+w[i];
		if(c<m)
			b=b+p[i];
		else
			return (b+(1-(c-m)/w[i]) * p[i]);
	}
	return b;
}

void knapsack::BKnap(int k,int cp,int cw)
{
	int j;

	if(cw+w[k]<=m)
	{
		y[k]=1;
		if(k<n)
			BKnap(k+1,cp+p[k],cw+w[k]);
		if((cp+p[k]>fp) && (k==n))
		{
			fp=cp+p[k];
			fw=cw+w[k];
			for(j=1;j<=k;j++)
				x[j]=y[j];
		}
	}

	if(Bound(cp,cw,k)>=fp)
	{
		y[k]=0;
		if(k<n)
			BKnap(k+1,cp,cw);
		if((cp>fp) && (k==n))
		{
			fp=cp;
			fw=cw;
			for(j=1;j<=k;j++)
				x[j]=y[j];
		}
	}
}

void knapsack::getdata()
{
	int i;

	for(i=1;i<=n;i++)
		cout<<"x["<<i<<"]= "<<x[i]<<endl;
}

void main()
{
	knapsack k;

	k.setdata();

	k.BKnap(1,0,0);

	cout<<"\nSolution is :\n";
	k.getdata();

	getch();
}