CA-LAB-program-program for LRU page replacement algorithm

#include<stdio.h>
main()
{ 
int q[20],p[50],c=0,c1,d,f,i,j,k=0,n,r,t,b[20],c2[20];
printf("Enter no of pages:"); 
scanf("%d",&n);
printf("Enter the reference string:");
for(i=0;i<n;i++) 
scanf("%d",&p[i]);
printf("Enter no of frames:"); 
scanf("%d",&f);
q[k]=p[k]; 
printf("\n\t%d\n",q[k]);
c++;
k++; 
for(i=1;i<n;i++)
{
c1=0; 
for(j=0;j<f;j++)
{
if(p[i]!=q[j])
c1++;
}
if(c1==f) 
{ 
c++;
if(k<f)
{ 
q[k]=p[i];
k++; 
for(j=0;j<k;j++) 
printf("\t%d",q[j]);
printf("\n");
}
else
{ 
for(r=0;r<f;r++)
{
c2[r]=0; 
for(j=i-1;j<n;j--)
{ 
if(q[r]!=p[j])
else
break;
} 
} 
for(r=0;r<f;r++)
b[r]=c2[r];
for(r=0;r<f;r++) 
{ 
for(j=r;j<f;j++)
{ 
if(b[r]<b[j])
{ 
t=b[r];
b[r]=b[j];
b[j]=t;
}
}
}
for(r=0;r<f;r++)
{
if(c2[r]==b[0])
q[r]=p[i]; 
printf("\t%d",q[r]);
}
printf("\n"); 
} 
}
} 
printf("\nThe no of page faults is %d",c);
}