cs-142:runs-in-random-numbers [CS Wiki]

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+<code cpp>
+//
+//  main.cpp
+//  Runsofthrees
+//
+//  Created by Kevin Seppi on 10/7/16.
+//  Copyright © 2016 Kevin Seppi. All rights reserved.
+//
+#include <iostream>
+#include <iomanip>
+#include <stdlib.h>
+#include <time.h>
+using namespace std;
+int main(int argc, const char * argv[]) {
+    const int MAX_FACE = 6;
+    const int LOOKING_FOR = 3;
+    const int NUMBER_OF_HUMAN_ROLLS = 10;
+    const int NUMBER_OF_ROLLS = 100;
+    const int NUMBER_OF_SIMULATIONS = 1000;
+    int dieFace = 0;
+    int currentRunLength = 0;
+    int longestRunLength = 0;
+    int totalLongestRunLength = 0;
+    double averageLongestRunLength = 0;
+    cout << fixed << setprecision(2);
+    srand(static_cast <unsigned int>(time(0)));
+    // try the following line instead and run the program twice!
+    // srand(42); // Same sequence of random numbers every time (nothing special about 42, just a particular sequence)
+    cout << "Count runs of: " << LOOKING_FOR << " in rolls of a die:" << endl;
+    cout << "First you try being the random number generator, give me (all at once or one at a time) ";
+    cout << NUMBER_OF_HUMAN_ROLLS << " int's in the range 1-6: ";
+    for (unsigned int i = 0; i < NUMBER_OF_HUMAN_ROLLS; i++) {
+        // Random roll of a 6 sided die
+        cin >> dieFace;
+        if (dieFace == LOOKING_FOR) {
+            currentRunLength++;
+            longestRunLength = max(longestRunLength, currentRunLength);
+        }
+        else {
+            currentRunLength = 0;
+        }
+    }
+    cout << endl;
+    cout << "Summary:" << endl;
+    cout << "The longest run of " << LOOKING_FOR << " was " << longestRunLength << endl;
+    cout << endl;
+    cout << "...interesting, now let's let the computer make random values:" << endl;
+    cout << endl;
+    cout << "Count runs of: " << LOOKING_FOR << " in rolls of a die:" << endl;
+    currentRunLength = 0;
+    longestRunLength = 0;
+    cout << "Random values form a 6-sided die:" << endl;
+    for (unsigned int i = 0; i < NUMBER_OF_ROLLS; i++) {
+        // Random roll of a 6 sided die
+        dieFace = rand() % MAX_FACE + 1;
+        cout << dieFace << " ";
+        if (dieFace == LOOKING_FOR) {
+            currentRunLength++;
+            longestRunLength = max(longestRunLength, currentRunLength);
+        }
+        else {
+            currentRunLength = 0;
+        }
+    }
+    cout << endl;
+    cout << "Summary:" << endl;
+    cout << "The longest run of " << LOOKING_FOR << " was " << longestRunLength << endl;
+    cout << endl;
+    cout << "...interesting, but what is the AVERAGE of the LONGEST runs over 1000 simulations?" << endl;
+    cout << "Let's try it:" << endl;
+    cout << endl;
+    cout << "Simulating..." << endl;
+    totalLongestRunLength = 0;
+    for (unsigned int i = 0; i < NUMBER_OF_SIMULATIONS; i++) {
+        currentRunLength = 0;
+        longestRunLength = 0;
+        for (unsigned int j = 0; j < NUMBER_OF_ROLLS; j++) {
+            dieFace = rand() % MAX_FACE + 1;
+            if (dieFace == LOOKING_FOR) {
+                currentRunLength++;
+                longestRunLength = max(longestRunLength, currentRunLength);
+            }
+            else {
+                currentRunLength = 0;
+            }
+        }
+        //cout << longestRunLength << endl;
+        totalLongestRunLength += longestRunLength;
+    }
+    cout << endl;
+    cout << "Summary:" << endl;
+    averageLongestRunLength = totalLongestRunLength/(static_cast<double>(NUMBER_OF_SIMULATIONS));
+    cout << "The average longest run of " << LOOKING_FOR << " was " << averageLongestRunLength << endl;
+    cout << endl;
+    system("pause");
+    return 0;
+}
+</code>

cs-142/runs-in-random-numbers.txt · Last modified: 2016/10/07 12:35 by kseppi

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