php8.0 버전 호환 코드 적용 및 PHP 끝 태그 삭제 일괄적용

lib/PHPExcel/Calculation/Engineering.php

@@ -768,7 +768,7 @@ class PHPExcel_Calculation_Engineering
         //    Split the input into its Real and Imaginary components
         $leadingSign = 0;
         if (strlen($workString) > 0) {
-            $leadingSign = (($workString{0} == '+') || ($workString{0} == '-')) ? 1 : 0;
+            $leadingSign = (($workString[0] == '+') || ($workString[0] == '-')) ? 1 : 0;
         }
         $power = '';
         $realNumber = strtok($workString, '+-');
@@ -809,16 +809,16 @@ class PHPExcel_Calculation_Engineering
      */
     private static function cleanComplex($complexNumber)
     {
-        if ($complexNumber{0} == '+') {
+        if ($complexNumber[0] == '+') {
             $complexNumber = substr($complexNumber, 1);
         }
-        if ($complexNumber{0} == '0') {
+        if ($complexNumber[0] == '0') {
             $complexNumber = substr($complexNumber, 1);
         }
-        if ($complexNumber{0} == '.') {
+        if ($complexNumber[0] == '.') {
             $complexNumber = '0'.$complexNumber;
         }
-        if ($complexNumber{0} == '+') {
+        if ($complexNumber[0] == '+') {
             $complexNumber = substr($complexNumber, 1);
         }
         return $complexNumber;