1 <?php 2 #二进制相加 3 function binary_plus($binstr1, $binstr2) { 4 $bin_arr1 = str_split($binstr1); 5 $bin_arr2 = str_split($binstr2); 6 $arr_len1 = count($bin_arr1); 7 $arr_len2 = count($bin_arr2); 8 $sum_arr = array(); 9 10 if ($arr_len1 < $arr_len2) { 11 $short_arr = &$bin_arr1; 12 } else { 13 $short_arr = &$bin_arr2; 14 } 15 16 #将两个数组的长度补到一样长，短数组在前面补0 17 for ($i = 0; $i < abs($arr_len1 - $arr_len2); $i++) { 18 array_unshift($short_arr, 0); 19 } 20 21 $carry = 0; #进位标记 22 for ($i = count($bin_arr1) - 1; $i >= 0; $i--) { 23 $result = $bin_arr1[$i] + $bin_arr2[$i] + $carry; 24 switch ($result) { 25 case 0: 26 array_unshift($sum_arr, 0); 27 $carry = 0; 28 break; 29 case 1: 30 array_unshift($sum_arr, 1); 31 $carry = 0; 32 break; 33 case 2: 34 array_unshift($sum_arr, 0); 35 $carry = 1; 36 break; 37 case 3: 38 array_unshift($sum_arr, 1); 39 $carry = 1; 40 break; 41 default: 42 die(); 43 } 44 } 45 46 if($carry == 1) { 47 array_unshift($sum_arr, 1); 48 } 49 50 return implode("", $sum_arr); 51 } 52 53 $bin1 = "1001101"; 54 $bin2 = "1010"; 55 print_r(binary_plus($bin1, $bin2)); 56 ?>
