"is_int" is not working properly? - php

Question

I am trying to check, Input is an integer, float or string. This program gives an error on negative inputs, I don't understand why this happen. When i check inputs with "ctype_digit()", is_int section escaped.
<?php
$var=fgets(STDIN);
if(is_numeric($var))
{
//print "$var";
if(ctype_digit($var) || is_int($var)){
print "$var";
print "This type of input is Integer";
}
else{
//print "$var";
print "This type of input is Float";
}
}
else{
print "This type of input is String";
}
?>

Answer 1

From PHP MANUAL :
ctype_digit
Note:
This function expects a string to be useful, so for example passing in an integer may not return the expected result. However, also note that HTML forms will result in numeric strings and not integers. See also the types section of the manual.
is_int
Note:
To test if a variable is a number or a numeric string (such as form input, which is always a string), you must use is_numeric().
Use a filter like this filter_var($var, FILTER_VALIDATE_INT) for an integer evaluation.
<?php
$var = -10.12;
if(is_numeric($var))
{
//print "$var";
if(filter_var($var, FILTER_VALIDATE_INT)){
var_dump(filter_var($var, FILTER_VALIDATE_INT));
print "$var";
print "This type of input is Integer";
}
else{
//print "$var";
print "This type of input is Float";
}
}
else{
print "This type of input is String";
}
?>

Answer 2

ctype fails with negative numbers because minus ("-") is not considered to be part of the POSIX digit character class ([0-9.]). My PHP (5.3) fails with negative strings '-1' as well.
Despite what others have said, filter_vars() is not the appropriate solution. It may be workable, but the OP is testing primitive values, not trying to sanitize user input. He is also asking why ctype() doesn't work, and for a variable test that does. filter_vars() also does not work in other common php versions (< 5.2). Furthermore, his test can be performed without added function calls.
instead of:
if(ctype_digit($var) || is_int($var))
cast it.
foreach (array (-1, 0, 1,1.1,'1.1','1','abc','0','-1') as $test)
{
if (is_numeric($test))
{
if ((int) $test == $test) // <-- HERE
{ echo "int: $test\n"; }
else
{ echo "float: $test\n"; }
}
else
{ echo "string: $test\n"; }
}
/*
returns:
int: -1
int: 0
int: 1
float: 1.1
float: 1.1
int: 1
string: abc
int: 0
int: -1
*/
Note: The (int) will turn any non-integer string into "1", and == against the string will also cast the string to a 1, so for "abc", the (int) 'abc' == 'abc' will produce 1 == 1 . That means either the numeric string test will have to happen first or some other pure string test has to happen first.
Note2: It will fail with strings with spaces. e.g " 1 ". Perhaps add $var=is_string($var) ? trim($var) : $var;