模拟 C++ 版本

#include <iostream>

using namespace std;

// 打表
string englishes[] = {"zero", "one", "two", "three", "four", 
                        "five", "six", "seven", "eight", "nine"};

int main(void) {
  string n;
  cin >> n;
  // corner case
  if (n == "0") return cout << "zero" << endl, 0;

  int sum = 0;
  for (const auto& c : n) sum += c - '0';

  string ans;
  while (sum) {
    ans = englishes[sum % 10] + ' ' +  ans;
    sum /= 10;
  }

  cout << ans << endl;
  return 0;
}

C语言版本

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

const char* englishes[] = {"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"};

int main(int argc, char** argv) {
    char num[200];
    scanf("%s", num);

    char* p = num;
    int s = 0;
    while (*p) {
        s += *p - '0';
        ++p;
    }

    char t[50];
    sprintf(t, "%d", s);
    p = t;
    while (*p) {
        printf("%s", *(englishes + *p - '0'));
        if (*(p + 1)) putchar(' ');
        ++p;
    }

    return 0;
}