update

content/courses/prog-intro/homeworks/sum/SumBigDecimalHex/SumBigDecimalHex.java

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+// SumBigDecimalHex.java
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+public class SumBigDecimalHex {
+  public static void main(String[] args) {
+      BigDecimal sum = new BigDecimal("0");
+      for (String argument : args) {
+          StringBuilder number = new StringBuilder();
+          for (char c : argument.toCharArray()) {
+              if (!Character.isWhitespace(c)) {
+                  number.append(c);
+              } else {
+                  sum = sum.add(parseNumber(number));
+                  number = new StringBuilder();
+              }
+          }
+
+          sum = sum.add(parseNumber(number));
+      }
+
+      System.out.println(sum);
+  }
+
+
+  static BigDecimal parseNumber(StringBuilder number) {
+      if (!number.isEmpty()) {
+          String numberString = number.toString().toLowerCase();
+          if (numberString.startsWith("0x")) {
+              numberString = numberString.substring(2);
+              if (numberString.contains("s")) {
+                  int indexOfS = numberString.indexOf('s');
+
+                  String mantissaHexString = numberString.substring(0, indexOfS);
+                  String exponentHexString = numberString.substring(indexOfS + 1);
+                  
+                  BigInteger mantissa = new BigInteger(mantissaHexString, 16);
+                  BigInteger exponent = new BigInteger(exponentHexString, 16);
+
+                  return new BigDecimal(mantissa).scaleByPowerOfTen(exponent.negate().intValueExact());
+              }
+              return new BigDecimal(new BigInteger(numberString, 16));
+          } else {
+              return new BigDecimal(numberString);
+          }
+      } else {
+          return BigDecimal.ZERO;
+      }
+  }
+}
+