Made some minor changes to B7 (page replacement in C++) code.

- Changed variable names
- Indentation and stuff
- Added description

Codes/Group B/Code-B7.cpp

@@ -1,136 +1,135 @@
+// Assignment-B7 - Page Replacement in C++ (LRU + Optimal)
+// BEGINNING OF CODE
+#include <cmath>
+#include <complex>
 #include <iostream>
 using namespace std;
 
-int refstring[] = {0, 2, 1, 6, 4, 0, 1, 0, 3, 1, 2, 1};
+int refString[] = {0, 2, 1, 6, 4, 0, 1, 0, 3, 1, 2, 1};
-int win, hit = 0, miss = 0, res[4], lastUsed[40];
+int window = 0, hit = 0, miss = 0, currentPages[4], lastUsed[40];
+int len = sizeof(refString) / sizeof(refString[0]);
 
 int findLRU() {
-    int minIndex = 0;
+  int min_index = 0;
-    for(int i = 1; i < win; i++){
+  for (int i=1; i<window; i++) {
-        if(lastUsed[i] < lastUsed[minIndex]){
+    if (lastUsed[i] < lastUsed[min_index]) {
-            minIndex = i;
+      min_index = i;
     }
   }
-    return minIndex;
+  return min_index;
 }
 
-void lru(int rf[], int len)
+void LRU() {
-{
+  for (int i=0; i<window; i++) {
-    for(int i = 0; i < win; i++) {
+    currentPages[i] = -1;
-        res[i] = -1;
     lastUsed[i] = -1;
   }
 
-    for(int j = 0; j < len; j++) {
+  for (int i=0; i<len; i++) {
     bool hitFlag = false;
-        for(int k = 0; k < win; k++){
+    for (int j=0; j<window; j++) {
-            if (res[k] == rf[j]){
+      if (currentPages[j] == refString[i]) {
         hit++;
-                lastUsed[k] = j;
         hitFlag = true;
+        lastUsed[j] = i;
         break;
       }
     }
-        if (!hitFlag) {
+    if (hitFlag == false) {
       miss++;
       bool emptyFound = false;
-            for(int k = 0; k < win; k++){
+      for (int j=0; j<window; j++) {
-                if (res[k] == -1){
+        if (currentPages[j] == -1) {
-                    res[k] = rf[j];
-                    lastUsed[k] = j;
           emptyFound = true;
+          currentPages[j] = refString[i];
+          lastUsed[j] = i;
           break;
         }
       }
-            if(!emptyFound){
+        if (emptyFound == false) {
-                int lruIndex = findLRU();
+          int lru_index = findLRU();
-                res[lruIndex] = rf[j];
+          currentPages[lru_index] = refString[i];
-                lastUsed[lruIndex] = j;
+          lastUsed[lru_index] = i;
         }
       }
   }
+  cout<<endl<<"----- LRU ------";
+  cout<<endl<<"Number of hits: "<<hit;
+  cout<<endl<<"Number of misses: "<<miss;
+}
 
-    cout<<"\nNo of hits (LRU): "<<hit;
+int findOptimal(int current_index) {
-    cout<<"\nNo of misses (LRU): "<<miss;
+  int max_index = -1, farthest = current_index;
-}
+  for (int i=0; i<window; i++) {
-
-int findOptimal(int rf[], int len, int currentIndex)
-{
-    int maxIndex = -1, farthest = currentIndex;
-    for(int i = 0; i < win; i++){
     int j;
-        for(j = currentIndex + 1; j < len; j++){
+    for (j=current_index+1; j<len; j++) {
-            if(res[i] == rf[j]){
+      if (currentPages[i] == refString[j]) {
         if (j > farthest) {
           farthest = j;
-                    maxIndex = i;
+          max_index = i;
         }
         break;
       }
     }
-        if(j == len)
+    if (j == len) {
       return i;
     }
-    return maxIndex;
+  }
+  return max_index;
 }
 
-void optimal(int rf[], int len){
+void Optimal() {
   hit = 0;
   miss = 0;
 
-    for(int i = 0; i < win; i++){
+  for (int i=0; i<window; i++) {
-        res[i] = -1;
+    currentPages[i] = -1;
   }
 
-    for(int j = 0; j < len; j++){
+  for (int i=0; i<len; i++) {
     bool hitFlag = false;
-        for(int k = 0; k < win; k++){
+    for (int j=0; j<window; j++) {
-            if (res[k] == rf[j]){
+      if (currentPages[j] == refString[i]) {
         hit++;
         hitFlag = true;
         break;
       }
     }
-        if (!hitFlag){
+    if (hitFlag == false) {
       miss++;
       bool emptyFound = false;
-            for(int k = 0; k < win; k++){
+      for (int j=0; j<window; j++) {
-                if (res[k] == -1){
+        if (currentPages[j] == -1) {
-                    res[k] = rf[j];
           emptyFound = true;
+          currentPages[j] = refString[i];
           break;
         }
       }
-            if(!emptyFound){
+      if (emptyFound == false) {
-                int optimalIndex = findOptimal(rf, len, j);
+        int optimal_index = findOptimal(i);
-                res[optimalIndex] = rf[j];
+        currentPages[optimal_index] = refString[i];
       }
     }
   }
+  cout<<endl<<"----- OPTIMAL -----";
+  cout<<endl<<"Number of hits: "<<hit;
+  cout<<endl<<"Number of misses: "<<miss;
+}
 
-    cout<<"\nNo of hits (Optimal): "<<hit;
+void display() {
-    cout<<"\nNo of misses (Optimal): "<<miss;
+  cout<<endl<<"Current pages are:\t";
+  for (int i=0; i<window; i++) {
+    cout<<currentPages[i]<<" ";
+  }
+  cout<<endl;
 }
 
-void display()
+int main() {
-{
+  cout<<endl<<"Enter window size:\t";
-    cout<<"\nPages in window are: \n";
+  cin>>window;
-    for(int i = 0; i < win; i++){
+  LRU();
-        cout<<res[i]<<"\n";
-    }
-}
-
-int main()
-{
-    cout<<"\nEnter window size: ";
-    cin>>win;
-    int len = sizeof(refstring)/sizeof(refstring[0]);
-
-    cout<<"\nBy LRU algorithm: ";
-    lru(refstring, len);
   display();
-
+  Optimal();
-    cout<<"\n\nBy Optimal Algorithm: ";
-    optimal(refstring, len);
   display();
 }
+// END OF CODE