<SCRIPT>
function sumDigits(num) {
var i, sum = 0; // can declare two variables at once
for (i = 1; i <= num; i++) {
sum += i; // add each number to sum (ie, 1 + 2 + ...+ num)
}
// Display result
alert("The sum of the digits from 1 to "+ num + " is:\n\n\t " + sum);
}
</SCRIPT>
<BODY>
Looping Functions - Calculate the sum of the digits.
<FORM NAME="SumNums">
The sum of the digits from 1 to:
<INPUT TYPE="text" NAME="charNum">
<INPUT TYPE="button" VALUE="Calculate"
onClick="sumDigits(SumNums.charNum.value)">
</FORM>
NOTE: sumDigits() brute forces the answers, the Mathematical approach would be to use the Formula:
var i, sum = 0; // can declare two variables at once
for (i = 1; i <= num; i++) {
sum += i; // add each number to sum (ie, 1 + 2 + ...+ num)
}
// Display result
alert("The sum of the digits from 1 to "+ num + " is:\n\n\t " + sum);
}
</SCRIPT>
<BODY>
Looping Functions - Calculate the sum of the digits.
<FORM NAME="SumNums">
The sum of the digits from 1 to:
<INPUT TYPE="text" NAME="charNum">
<INPUT TYPE="button" VALUE="Calculate"
onClick="sumDigits(SumNums.charNum.value)">
</FORM>
NOTE: sumDigits() brute forces the answers, the Mathematical approach would be to use the Formula:
n (n + 1) / 2.
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