Verify VIN

vin_check.cc

#include <vector>
#include <iostream>
#include <map>
#include <functional>
#include <numeric>

using namespace std;

#define VIN_LEN             17
#define VIN_CHECKDIGIT_POS  8
#define VIN_X_CHECK_DIGIT   ('X' - '0')
typedef std::vector<size_t> vin_vec;

size_t vin_transliterate(char value) 
{
    char lv = (char)std::tolower(value);
    std::map<char, size_t> m = {{'a', 1}, {'b', 2}, {'c', 3}, {'d', 4}, {'e', 5}, {'f', 6}, {'g', 7}, {'h', 8},
                                {'j', 1}, {'k', 2}, {'l', 3}, {'m', 4}, {'n', 5},           {'p', 7},            {'r', 9},
                                          {'s', 2}, {'t', 3}, {'u', 4}, {'v', 5}, {'w', 6}, {'x', 7}, {'y', 8},  {'z', 9}};

    if( lv == 'o' || lv == 'i' || lv == 'q' ) {
        return -1;
    }

    if( value <= '9' ) {
        return value - '0';
    }

    return m[lv];
}

vin_vec vin_str_to_tl_vec(std::string vin_string) 
{
    vin_vec ret;

    for(string::iterator it = vin_string.begin() ; it < vin_string.end(); it++) {
        size_t t_ret = vin_transliterate((char)*it);

        if( t_ret != -1 ) {
            ret.push_back(t_ret);
        } 
    }

    return ret;
}

bool vin_check_digit(std::string vin)
{
    static const size_t vin_wgt_factor_array[] = {8,7,6,5,4,3,2,10,0,9,8,7,6,5,4,3,2};
    vin_vec vin_weight_factor (vin_wgt_factor_array,vin_wgt_factor_array + sizeof(vin_wgt_factor_array) / sizeof(vin_wgt_factor_array[0]));

    char check_digit = vin.at(VIN_CHECKDIGIT_POS) - '0';
    vin_vec tl_vec = vin_str_to_tl_vec(vin);

    if (tl_vec.size() != VIN_LEN) {
        return false;
    }

    size_t cumul = std::inner_product(tl_vec.begin(), tl_vec.end(), vin_weight_factor.begin(), 0); 
    char t_mod = cumul % 11;
    
    return (((cumul % 11) == 10 ? VIN_X_CHECK_DIGIT : t_mod) == check_digit);
}

Note: This will require compilation by a C++11 compiler (-std=c++11)