# help calculator

i need help making the tip rate work. so it doesnt only do the 15% but whatever percent you choose

if (array_key_exists(‘Calculate’,\$_POST)){
// for the first exercise
\$userBill = \$_POST[‘bill’];
if (is_numeric(\$userBill)) {
\$suggestedTip = calTip(\$userBill);
\$output = “The suggested tip is \$suggestedTip”;
} else {
}
}

``````function calTip(\$bill){
\$tip = \$bill * 0.15;
return \$tip;
}
``````

Tip Calculator

What is the amount of the bill? \$
What is the tip rate? %
<?php echo "
"; echo \$output; ?>

i would think i could put

\$tip = \$bill * \$tipRate??

but then i get The suggested tip is 0 everytime

wehere do u get the billrate from?

btw:
a little function u that would be userfull:
[php]// makes nice to view nums within the range given by \$error
// e.g. 314 -> 300, 321 -> 320, 344 -> 350 …
function roundnice(\$num,\$digits=0,\$error=.05,\$errorTo5=NULL)
{
if(\$errorTo5===NULL)\$errorTo5=\$error/2;
\$digits=pow(10,\$digits);
\$num*=\$digits;
\$max=\$num*(1+\$error);
\$min=\$num*(1-\$error);
\$maxTo5=\$num*(1+\$errorTo5);
\$minTo5=\$num*(1-\$errorTo5);
\$len=1;
while(\$num>=pow(10,\$len))\$len++;

for(\$i=\$len-1;\$i>0;\$i–)
{
\$round=round(\$num/pow(10,\$i)/5)*pow(10,\$i)*5;
if(\$round<\$maxTo5 and \$round>\$minTo5) return \$round/\$digits;
\$round=round(\$num/pow(10,\$i))*pow(10,\$i);
if(\$round<\$max and \$round>\$min) return \$round/\$digits;
}
\$round=round(\$num/pow(10,\$i)/5)*pow(10,\$i)*5;
if(\$round<\$maxTo5 and \$round>\$minTo5) return \$round/\$digits;
return round(\$num)/\$digits;
}
[/php]

so it woun’t return numbers like 2,99 but 3,00 instead