cooked 3

2026-05-16 19:35:27 +00:00 · 2026-05-14 08:02:24 +05:30
parent 447e01fbc3
commit 1226e432cd
12 changed files with 538 additions and 0 deletions
@@ -0,0 +1,109 @@
+#include <stdio.h>
+#include <string.h>
+
+#define MAX 50
+
+// ── FIFO ──────────────────────────────────────────────────────────────────
+void fifo(int pages[], int n, int frames) {
+    int mem[MAX], front = 0, faults = 0;
+    memset(mem, -1, sizeof(mem));
+
+    printf("\n--- FIFO ---\n");
+    printf("Page\tFrames\t\t\tFault\n");
+
+    for (int i = 0; i < n; i++) {
+        int found = 0;
+
+        // check if page already in memory
+        for (int j = 0; j < frames; j++)
+            if (mem[j] == pages[i]) { found = 1; break; }
+
+        printf("%d\t", pages[i]);
+
+        if (!found) {
+            mem[front] = pages[i];       // replace oldest page
+            front = (front + 1) % frames;
+            faults++;
+
+            for (int j = 0; j < frames; j++)
+                if (mem[j] == -1) printf("- "); else printf("%d ", mem[j]);
+            printf("\t\tFault");
+        } else {
+            for (int j = 0; j < frames; j++)
+                if (mem[j] == -1) printf("- "); else printf("%d ", mem[j]);
+        }
+        printf("\n");
+    }
+
+    printf("Total Page Faults: %d\n", faults);
+}
+
+// ── OPTIMAL ───────────────────────────────────────────────────────────────
+void optimal(int pages[], int n, int frames) {
+    int mem[MAX], faults = 0, count = 0;
+    memset(mem, -1, sizeof(mem));
+
+    printf("\n--- Optimal ---\n");
+    printf("Page\tFrames\t\t\tFault\n");
+
+    for (int i = 0; i < n; i++) {
+        int found = 0;
+
+        // check if page already in memory
+        for (int j = 0; j < frames; j++)
+            if (mem[j] == pages[i]) { found = 1; break; }
+
+        printf("%d\t", pages[i]);
+
+        if (!found) {
+            if (count < frames) {
+                // frames not full yet, just fill
+                mem[count++] = pages[i];
+            } else {
+                // find which page in memory is used farthest in future
+                int replaceIdx = -1, farthest = -1;
+                for (int j = 0; j < frames; j++) {
+                    int nextUse = n;  // assume never used again
+                    for (int k = i + 1; k < n; k++) {
+                        if (pages[k] == mem[j]) { nextUse = k; break; }
+                    }
+                    if (nextUse > farthest) {
+                        farthest = nextUse;
+                        replaceIdx = j;
+                    }
+                }
+                mem[replaceIdx] = pages[i];
+            }
+            faults++;
+
+            for (int j = 0; j < frames; j++)
+                if (mem[j] == -1) printf("- "); else printf("%d ", mem[j]);
+            printf("\t\tFault");
+        } else {
+            for (int j = 0; j < frames; j++)
+                if (mem[j] == -1) printf("- "); else printf("%d ", mem[j]);
+        }
+        printf("\n");
+    }
+
+    printf("Total Page Faults: %d\n", faults);
+}
+
+// ── MAIN ──────────────────────────────────────────────────────────────────
+int main() {
+    int pages[MAX], n, frames;
+
+    printf("Enter number of pages in reference string: ");
+    scanf("%d", &n);
+    printf("Enter reference string: ");
+    for (int i = 0; i < n; i++)
+        scanf("%d", &pages[i]);
+
+    printf("Enter number of frames: ");
+    scanf("%d", &frames);
+
+    fifo(pages, n, frames);
+    optimal(pages, n, frames);
+
+    return 0;
+}