<?php
 
 
function is10x($userInput) {
	$input = trim($userInput);
	$binStr = sprintf('%b', intval($input,2));
	if( $binStr !== $input) return FALSE;
	return array_sum(str_split($binStr)) === 1;
}
 
// tests
function test($userInput, $expected) {
	printf( "%-10s \t%s\n", '>'.$userInput.'<', is10x($userInput) === $expected ?'passed':'failed');
}
for($i=0; $i<8; $i++) test( (String)pow(10, $i), TRUE);
for($i=0; $i<8; $i++) test( pow(10, $i), TRUE);
test( '10000001', FALSE);
test( '12345', FALSE);
test( ' 0001  ', FALSE);
test( 'a0b11', FALSE);
test( '0b1111', FALSE);
test( '000', FALSE);
test( '0', FALSE);
 

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