Data Structure Knapsack Problem

/* Knapsack Problem Using Backtracking*/
#include<stdio.h>
int x[12],w[12],pr[12],m,n,z,val;
void main()
{

int k,i;
float r=0;
void knapsack(float,int,float);
int s1=0;
clrscr();
printf("\n\n\t\tKNAPSACK PROBLEM USING BACKTRACKING\n\n");
printf("\n\tEnter the No. of Items : ");
scanf("%d",&n);
printf("\n\tEnter the Weight & Value for the Items \n");
for(i=0;i<n;i++)
{
printf("\n\titem %d : ",i+1);
scanf("%d%d",&w[k],&pr[k]);
r+=w[k];
s1+=pr[k];
}
printf("\n\n\t\tEnter the Knapsack Capacity : ");
scanf("%d",&m);
printf("\n\n\tITEMS IN THE KNAPSACK\n\n");
printf("\titem\tweight\tvalue\n\n");
knapsack(0,1,r);
getch();
}
void knapsack(float s,int k,float r)
{
int j,p;
x[k]=1;
if(s+w[k]==m)
{
printf("%d Set\n",++z);
for(j=1;j<=k;j++)
{
if(x[j])
{
printf("\n%d\t%d\t",j,w[j]);
printf("%d ",pr[j]);
}
}
printf("\n\n");
}
else if(s+w[k]+w[k+1]<=m)
knapsack(s+w[k],k+1,r-w[k]);
if((s+r-w[k]>=m) && (s+w[k+1]<=m))
{
x[k]=0;
knapsack(s,k+1,r-w[k]);
}
}