通过移除给定字符串中存在的十六进制表示中的字符来修改数组

#include <bits/stdc++.h>
using namespace std;
string decimalToHexa(int num){
   if (num == 0) {
      return "0";
   }
   // char array to store hexadecimal number
   char alpha[] = {'A', 'B', 'C', 'D', 'E', 'F'};
   string Hexa;
   // Traverse the number until it becomes zero
   while (num > 0) {
      // if the remainder is less than 10, store it as it is
      if (num % 16 < 10) {
          Hexa += to_string(num % 16);
      } else {
          // else store the character
          Hexa += alpha[num % 16 - 10];
      }
      // divide the number by 16
      num /= 16;
   }
   // reverse the string
   reverse(Hexa.begin(), Hexa.end());
   return Hexa;
}
int hexaToDecimal(string modifiedHex) {
   // stores hexadecimal to decimal
   char mp[] = {10, 11, 12, 13, 14, 15};
   // Stores result
   int res = 0;
   int pos = 0;
   // reverse the string
   reverse(modifiedHex.begin(), modifiedHex.end());
   // Traverse the string
   for (char ch : modifiedHex) {
      // If a digit, multiply it with 16^pos
      if (isdigit(ch)) {
          res += ((int)pow(16, pos)) * (ch - '0');
      }
      // If character, multiply it with 16^pos
      else {
          res += ((int)pow(16, pos)) * mp[ch - 'A'];
      }
      // Increment the position
      pos += 1;
   }
   // Return the answer
   return res;
}
string removeChars(string hexaVal, string hex) {
   // set to store the characters of the given string
   set<char> charSet;
   // insert the characters of the given string in the set
   for (char ch : hex) {
      charSet.insert(ch);
   }
   // string to store the final hexadecimal number
   string res = "";
   // traverse the hexadecimal number string
   for (char ch : hexaVal) {
      // if the character is present in the set, then continue
      if (charSet.find(ch) != charSet.end()) {
          continue;
      }
      // else add the character to the final string
      res += ch;
   }
   // return the final string
   return res;
}
// function to modify the array as per the given condition
void changeArr(int array[], int N, string hex) {
   // Traverse the array
   for (int i = 0; i < N; i++) {
      // covnert the number to hexadecimal
      string hexa = decimalToHexa(array[i]);
      // remove the characters from the hexadecimal number string which are present in the given string
      string modifiedHex = removeChars(hexa, hex);
      // change the hexadecimal number to decimal
      int decVal = hexaToDecimal(modifiedHex);
      // replace the number with the new decimal value
      array[i] = decVal;
   }
   cout << "The final array after converting a number to hexadecimal, removing characters which are present in the string, and converting back to decimal is " << endl;
   // Print the modified array
   for (int i = 0; i < N; i++) {
      cout << array[i] << " ";
   }
}
int main() {
   // Given array
   int array[] = {54, 43,56,9999,1234, 32};
   int N = sizeof(array) / sizeof(array[0]);
   // Given string
   string hex = "1BCFE234";
   changeArr(array, N, hex);
   return 0;
}