批量把16进制转成10进制（c++）特别长的16进制字符串

缘由：批量把特别长的16进制字符串，转成10进制，而excel转完会缺失很多位。

下面是C++代码，运行完，断点查看转换结果，或者打印出来也行

/*
* 将十六进制数字组成的字符串（不包含前缀0x或0X）转换为与之等价的整型值
*/
#include <stdio.h>
#include <iostream>
#include <string>
#include <vector>
#include <math.h>
using namespace std;
/* 将十六进制中的字符装换为对应的整数 */
long long hexchtoi(char hexch)
{
    char phexch[] = "ABCDEF";
    char qhexch[] = "abcdef";
    for (long long i = 0; i < 6; i++)
        if ((hexch == phexch[i]) || (hexch == qhexch[i]))
            return 10 + i;

    return hexch-48; /* 非十六进制字符 */
}
long long htoi(const char s[])
{
    long long n = 0; /*有n位*/
    long long i = 0;
    long long answer = 0;
    /* 有效性检查 */
    while ((s[i] != '\0')) {
        if ((s[i] < '0') && (s[i] > '9'))
            if (hexchtoi(s[i]) >= 0)
                return 0;
        n++;
        i++;
    }
    for (long long j = 0; j < n; j++)
        answer += ((long long)pow(16, j) * hexchtoi(s[i - j - 1]));

    return answer;
}
int main()
{
    vector<const char*> vecInput;
    vecInput.push_back("11F000000000233C");
    vecInput.push_back("11F000000000100B");
    vecInput.push_back("11F00000000007A8");
    vecInput.push_back("11F000000000145B");
    vecInput.push_back("11F0000000000F18");
    vector<long long> vecRes;
    for (size_t i = 0; i < vecInput.size(); i++)
    {
        vecRes.push_back(htoi(vecInput[i]));
    }
    printf("-------stop----------");
}