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  1. <?php
  2.  
  3. //Калькулятор
  4. error_reporting(-1);
  5. mb_internal_encoding('utf-8');
  6.  
  7. $input = '243+6743-78*2='; //13816
  8. //$input = '1+2*3='; //9
  9. //$input = "321+3-2=";
  10. $inputLength = mb_strlen($input);
  11.  
  12. $number = 0; //Текущее число
  13. $result = 0; //Результат предыдущих действий
  14. $op = ''; // Предыдущая операция
  15.  
  16. for ($i = 0; $i < $inputLength; $i++) {
  17.     $char = mb_substr($input, $i, 1);
  18.     if ($char == '*' || $char == '+' || $char == '-' || $char == '=') {
  19.  
  20.         if ($op == '+') {
  21.             $result += $number;
  22.         }
  23.  
  24.         if ($op == '-') {
  25.             $result -= $number;
  26.         }
  27.  
  28.         if ($op == '*') {
  29.             $result *= $number;
  30.         }
  31.  
  32.         echo "op=[{$op}]  result = [{$result}]  number = [{$number}] char = [{$char}] \n";
  33.  
  34.         if ($result == 0) {
  35.             $result = $number;
  36.         }
  37.         $op = $char;
  38.         $number = 0;
  39.  
  40.         if ($char == "=") {
  41.             echo "Ответ: {$input}{$result}";
  42.         }
  43.  
  44.     } elseif (is_numeric($char)) {
  45.         $number = $number * 10 + $char;
  46.     } else {
  47.         echo "Неверный символ: {$char}\n";
  48.     }
  49.  
  50. }
  51.  
Success #stdin #stdout 0.03s 52480KB
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stdin
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Standard input is empty
stdout
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op=[]  result = [0]  number = [243] char = [+] 
op=[+]  result = [6986]  number = [6743] char = [-] 
op=[-]  result = [6908]  number = [78] char = [*] 
op=[*]  result = [13816]  number = [2] char = [=] 
Ответ: 243+6743-78*2=13816
https://ideone.com/1Nk5P2
language:
PHP (php 7.3.5)
created:
7 years ago
visibility:
public

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