Input N in PHP and judge from 1 ~ Number of times 1 appears in the decimal number of N Sequence

1 <? PHP 2 # input n to judge from 1 ~ Number of occurrences of 1 in the decimal number of N sequence 3 # For example, input 12, numbers containing 1 are, here 1 appears 5 times in total 4 5 # Number of times to judge the occurrence of 1 in decimal number 6 function count1dec ($ X) {7 $ I = 1; 8 $ COUNT = 0; 9 10 # obtain each digit of X from the single digit, and determine if it is 111 while ($ x> = POW (10, $ I-1 )) {12 $ r = floor ($ X % POW (10, $ I)/POW (10, $ I-1); 13 if ($ r = 1) {14 $ count ++; 15} 16 $ I ++; 17} 18 19 return $ count; 20} 21 22 # determine the number of occurrences of the entire sequence 1 23 function count1dec_seq ($ n) {24 $ COUNT = 0; 25 for ($ I = 1; $ I <= $ N; $ I ++ ) {26 $ count + = count1dec ($ I); 27} 28 return $ count; 29} 30 31 echo count1dec_seq (12); 32?>