factorial

parital week 4 tutorial solution

by Brian von Konsky

HTML

<div id="result">
</div>

CSS

th {color: blue;}

.n {color: red}

.factorial {color: green;}

JavaScript

// Compute n! using a recursive function
function factorialRecursive (n) {
    var value;
    if (n==0)
        value = 1;
    else if (n>0)
        value = factorialRecursive(n-1) * n;
    return value;    
}

// Compute n! using an iterative function
function factorialIterative (n) {
    var value;
    if (n >= 0) {
        value = 1;
        for (var i=2 ; i<=n; i++)
            value *= i;
    }
    return value;
}

function factorialTable(maxN, fact) {
    //start off the table
    var HTML="<table>";
    
    // Add the header
    HTML += "<th> n </th>";
    HTML += "<th> n! </th>";
    
    // Loop through up to and including hte last value in the table
    for (var n=0 ; n<=maxN ; n++) {
        HTML += "<tr>";
        HTML += "<td class='n'> " + n + " </td>";
        var nf = fact(n);
        HTML += "<td class='factorial'> " + nf + " </td>";
        HTML += "</tr>";
    }
    
    // Finish up.
    HTML += "</table>";
    return HTML;
}

// Get results for the recursive solution"
var HTML = "<h2> Recursive Solution </h2>";
HTML +=  factorialTable(10, factorialRecursive);

// Get the results for the iterative solution
HTML += "<h2> Iterative Solution </h2>";
HTML += factorialTable(10, factorialIterative);

// Display the results
document.getElementById("result").innerHTML = HTML;