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  1.  #include <iostream>
  2.  #include <string>
  3.  #include <map>
  4.  #include <cctype>
  5.  #include <algorithm>
  6.  
  7.  using namespace std;
  8.  
  9.  int convert2i(char item) {
  10.      static bool isFirst = true;
  11.      static map<char, int>lookup;
  12.      if(isFirst){
  13.          for(int i=0;i<16;++i)
  14.              lookup["0123456789ABCDEF"[i]]=i;
  15.          isFirst = false;
  16.      }
  17.      return lookup[::toupper(item)];
  18.  }
  19.  
  20.  char convert2C(int num){
  21.      static bool isFirst = true;
  22.      static map<int, char>lookup;
  23.      if(isFirst){
  24.          for(int i=0;i<16;++i)
  25.              lookup[i]="0123456789ABCDEF"[i];
  26.          isFirst = false;
  27.      }
  28.      return 0 <= num && num <= 15 ? lookup[num] : -1;
  29.  }
  30.  
  31.  void addition(char hexDecOne[10], char hexDecTwo[10], char (&hexDecSum)[10]) {
  32.      int carry = 0;
  33.      for (int i = 0; i < 9; i++) {// 9 : 10-1 (-1 for EOS)
  34.          int wk = convert2i(hexDecOne[i]) + convert2i(hexDecTwo[i]) + carry;
  35.          if(wk < 16){
  36.              carry = 0;
  37.          } else {
  38.              carry = 1;
  39.              wk -= 16;
  40.          }
  41.          hexDecSum[i] = convert2C(wk);
  42.      }
  43.      if(carry)
  44.          cerr << "overflow in addition" << endl;
  45.  }
  46.  
  47.  int main(void){
  48.      char hex1[10] = "000000001";
  49.      char hex2[10] = "00000000F";
  50.      char sum[10];
  51.  
  52.      addition(hex1, hex2, sum);
  53.      reverse(sum, sum+sizeof(sum)-1);//reverse(&sum[0], &sum[9]);//[0,9)
  54.      cout << string(sum) << endl;//000001AA9
  55.  }
Success #stdin #stdout #stderr 0s 3432KB
comments (?)
stdin 
Standard input is empty
stdout 
000000000���a�
stderr 
overflow in addition
https://ideone.com/MEYnIg
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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