FIFO changed

Author: hardikrana11

LAB9/fifo.cpp

@@ -1,70 +1,67 @@
 #include<bits/stdc++.h>
-
 using namespace std;
 
-int main()
+int present(int table_frame[], int nf, int page)
 {
-    int n,i,j;
-    printf("enter total number of pages\n");
-    scanf("%d",&n);
+	for(int i=0; i<nf; i++)
+		if(page == table_frame[i])
+			return 1;
+	return 0;
+}
 
-    int ref_str[n];
-    printf("enter reference string of pages\n");
-    for(i=0;i<n;i++)
-    {
-     scanf("%d",&ref_str[i]);
-    }
+void printtable(int table_frame[], int nf)
+{
+	for(int i=0; i<nf; i++)
+	{
+		if(table_frame[i] == -1)
+			printf("-- ");
+		else
+			printf("%2d ", table_frame[i]);
+	}
+	printf("||");
+}
+
+
+int main()
+{
+    //nf-number of frames
+    int n,nf,i,pos=0;
 
-    int frames;
-    printf("enter Total Number of Frames:\n");
+    printf("enter number of frames\n");
+    scanf("%d",&nf);
+    int table_frame[nf];
+    for(i=0;i<nf;i++)
     {
-        scanf("%d", &frames);
+        table_frame[i]=-1;
     }
 
-    int a[frames],pf=0;  //pf ..page faults
-    for(i=0;i<frames;i++)
+    printf("enter total number of page requests\n");
+    scanf("%d",&n);
+    int pages[n];
+    printf("enter reference string\n");
+    for(i=0;i<n;i++)
     {
-        a[i]=-1;
+        scanf("%d",&pages[i]);
     }
-    printf("allocation of frames to process is as following\n");
-
-    printf("ref_string\t\tpage_frames\n");
 
+    int count1=0;
+    printf("position of frame table after each request\n");
     for(i=0;i<n;i++)
     {
-
-        int s=0;
-        for(j=0;j<frames;j++)
+        printf("page table after request from %2d || ",pages[i]);
+        if(!present(table_frame,nf,pages[i]))
         {
-            if(ref_str[i]==a[j])
-            {
-                s++;
-                pf--;  //page hit
-            }
+           table_frame[pos] = pages[i];
+           pos = (pos+1)%nf ;//considering it as a queue
+           printtable(table_frame,nf);
+           printf("page fault\n");
+           count1++;
+           continue;
         }
 
-        pf++;
-
-        if((pf<=frames) && (s==0))
-        {
-            a[i]=ref_str[i];
-        }
-        else if(s==0)
-        {
-            a[(pf-1)%frames] = ref_str[i];
-        }
-         printf("\n");
-         printf("%d\t\t",ref_str[i]);
-         for(int k= 0;k<frames;k++)
-         {
-            printf("%d\t", a[k]);
-         }
+        printtable(table_frame,nf);
+		printf("\n");
 
     }
-
-      printf("\nTotal Page Faults=%d\n", pf);
-
-      //printf("total page hit is=%d\n",n-pf);
-
-      return 0;
+    printf("\nNumber of page faults : %d\n\n", count1);
 }