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copied!<h1>Short answer</h1> <p>This will solve your problem</p> <pre><code>function make_integer($num){ if ((int)$num != $num){ $temp = $num; while ((int)$temp != $temp){ $temp *= 10; } return $temp; } return $num; } </code></pre> <h1>Long Answer</h1> <p>The problem is that <code>is_int</code> does not test if your value is an integer or not. It will test if its <em>type</em> is an integer or not. So <code>is_int($var)</code> will do the same as if you ran <code>gettype($var) == 'integer'</code>. </p> <p>Some basic tests:</p> <pre><code>is_int((int) 0.57); # returns true, because the type is an int. is_int((float) 4); # returns false, because the type is a float is_int(10 * 0.2); # returns false, because int*float will be typecasted to a float </code></pre> <p>To make your code work, and to test if a <em>value</em> is an integer, you should cast your variable to an integer and then test if it is still equal to the original variable, like this:</p> <pre><code>(int) $var == $var; # will return true if the value is int </code></pre> <p>To fix your code, substitute the <code>!is_int($num)</code> with <code>(int) $num != $num</code> and <code>!is_int($temp)</code> with <code>(int) $temp != $temp</code>, just like the code in the short answer above.</p> <p>But, I can't resist to give an alternative solution to your problem. Personally, I would opt to use recursion for this problem. Like this:</p> <pre><code>function make_integer($num) { return (int)$num == $num ? $num : make_integer($num * 10); } </code></pre> <p>Or if you dislike the ternary operator:</p> <pre><code>function make_integer($num) { if ((int)$num == $num) return $num; # We're all done! else return make_integer($num * 10); # Try to increase by 10 } </code></pre> <h1>Even longer answer</h1> <p>The type casting of php will take some time to learn. In general, PHP will allways try to type cast if it can. When you multiply an integer with a float, the result will be a float, even if it "looks" like an integer.</p> <p>So try this code and pay special attention to the output:</p> <pre><code>$var = 0.03; var_dump($var); # float(0.03) var_dump(gettype($var)); # string(6) "double" var_dump(is_int($var)); # bool(false) </code></pre> <p>Now, if you multiply by the integer 100, php will stick the float, as <code><float>*<int></code> multiplication allways will result in a float, regardless of the value.</p> <pre><code>$var *= 100; # (100 * 0.03) var_dump($var); # float(3) var_dump(gettype($var)); # string(6) "double" var_dump(is_int($var)); # bool(false) </code></pre> <p>Note that the value is a natural number, but the type is still a float, and thus is_int will not return true.</p> <p>To test if a actual <em>value</em> of a variable is indeed an integer, we will need to do our own little trick with manual typecasting.</p> <pre><code>$var = 2.33; var_dump($var); # float(2.33) $var = (int) $var; var_dump($var); # int(2) </code></pre> <p>Note that when we tried to cast a float to an int the value changed. But if we try to cast a float that <em>is</em> an integer to an int, the value remains unaffected, only the <em>type</em> gets changed:</p> <pre><code>$var = 2.0; var_dump($var); # float(2) $var = (int) $var; var_dump($var); # int(2) </code></pre> <p>And now, remember how <code><int>*<float></code> resulted in a float? PHP will work in the same way when you do comparisons. In php, <code>"2.0" == 2</code> will be <code>true</code> because of this automatic typecasting. So when you do <code><int> == <float></code> what really happens is <code>(float)<int> == <float></code>.</p> <p>So what happens if we do <code>(float)(int)0.3</code>. First we typecast 0.3 to int(0), then we typecast back to float(0). Obviously, <code>float(0) == float(0.3)</code> will be <code>false</code>. But <code>(float)(int)3.0</code> will be cast first to int(3) then to float(3), which was the same value we started with.</p> <pre><code>$var = 3.0; var_dump($var); # float(3) $var = (int) $var; var_dump($var); # int(3) $var = (float) $var; var_dump($var); # float(3) </code></pre> <p>So if we do <code>(int) 3.0 == 3.0</code>, it will result in <code>(float)(int) 3.0 == 3.0</code> which is <code>true</code>.</p> <p>So the way to test if a value is integer is to do</p> <pre><code>(int)$var == $var </code></pre>

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