Finished experiments exercise

cometbroom · cometbroom · commit 420936376baa · 2022-02-11T13:01:31.000+01:00
diff --git a/Week3/prep-exercises/2-experiments/index.js b/Week3/prep-exercises/2-experiments/index.js
@@ -1,46 +1,59 @@
 "use strict";
 
 function runExperiment(sampleSize) {
-  const valueCounts = [0, 0, 0, 0, 0, 0];
-
-  // TODO
-  // Write a for loop that iterates `sampleSize` times (sampleSize is a number).
-  // In each loop iteration:
-  //
-  // 1. Generate a random integer between 1 and 6 (as if throwing a six-sided die).
-  // 2. Add `1` to the element of the `valueCount` that corresponds to the random
-  //    value from the previous step. Use the first element of `valueCounts`
-  //    for keeping a count how many times the value 1 is thrown, the second
-  //    element for value 2, etc.
-
-  const results = [];
-
-  // TODO
-  // Write a for..of loop for the `valueCounts` array created in the previous
-  // loop. In each loop iteration:
-  // 1. For each possible value of the die (1-6), compute the percentage of how
-  //    many times that value was thrown. Remember that the first value of
-  //    `valueCounts` represent the die value of 1, etc.
-  // 2. Convert the computed percentage to a number string with a precision of
-  //    two decimals, e.g. '14.60'.
-  // 3. Then push that string onto the `results` array.
-
-  return results;
+    const valueCounts = [0, 0, 0, 0, 0, 0];
+
+    // TODO
+    // Write a for loop that iterates `sampleSize` times (sampleSize is a number).
+    // In each loop iteration:
+    //
+    // 1. Generate a random integer between 1 and 6 (as if throwing a six-sided die).
+    // 2. Add `1` to the element of the `valueCount` that corresponds to the random
+    //    value from the previous step. Use the first element of `valueCounts`
+    //    for keeping a count how many times the value 1 is thrown, the second
+    //    element for value 2, etc.
+    for (let i = 0; i < sampleSize; ++i) {
+        let randIdx = Math.floor(Math.random() * valueCounts.length);
+        valueCounts[randIdx] += 1;
+    }
+
+    const results = [];
+
+    // TODO
+    // Write a for..of loop for the `valueCounts` array created in the previous
+    // loop. In each loop iteration:
+    // 1. For each possible value of the die (1-6), compute the percentage of how
+    //    many times that value was thrown. Remember that the first value of
+    //    `valueCounts` represent the die value of 1, etc.
+    // 2. Convert the computed percentage to a number string with a precision of
+    //    two decimals, e.g. '14.60'.
+    // 3. Then push that string onto the `results` array.
+    let sum = valueCounts.reduce((a, b) => a + b);
+
+    for (let i = 0; i < valueCounts.length; ++i) {
+        results.push(((valueCounts[i] * 100) / sum).toFixed(2).toString());
+    }
+
+    return results;
 }
 
 function main() {
-  const sampleSizes = [100, 1000, 1000000];
-
-  // TODO
-  // Write a for..of loop that calls the `runExperiment()` function for each
-  // value of the `sampleSizes` array.
-  // Log the results of each experiment as well as the experiment size to the
-  // console.
-  // The expected output could look like this:
-  //
-  // [ '26.00', '17.00', '10.00', '19.00', '16.00', '12.00' ] 100
-  // [ '14.60', '17.10', '19.30', '15.50', '16.70', '16.80' ] 1000
-  // [ '16.71', '16.68', '16.69', '16.66', '16.67', '16.59' ] 1000000
+    const sampleSizes = [100, 1000, 1000000];
+
+    runExperiment(100);
+    // TODO
+    // Write a for..of loop that calls the `runExperiment()` function for each
+    // value of the `sampleSizes` array.
+    // Log the results of each experiment as well as the experiment size to the
+    // console.
+    // The expected output could look like this:
+    //
+    // [ '26.00', '17.00', '10.00', '19.00', '16.00', '12.00' ] 100
+    // [ '14.60', '17.10', '19.30', '15.50', '16.70', '16.80' ] 1000
+    // [ '16.71', '16.68', '16.69', '16.66', '16.67', '16.59' ] 1000000
+    for (const sampleSize of sampleSizes) {
+        console.log(runExperiment(sampleSize), sampleSize);
+    }
 }
 
 main();
