思路：直接模拟，没测试代码能否通过。。。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string.h>
using namespace std;
char a[][10]={"*","',.!?","abcABC","defDEF","ghiGHI","jklJKL","mnoMNO","pqrsPQRS","tuvTUV","wxyzWXYZ"};

int main()
{
   char b[505];
   int cnt1, k = 0,  cnt2 = 0, len;
   while(cin >> b)
   {
   	  len = strlen(b);
      b[len] = '0';
      for(int i = 0; i < len; i++)
      {
	    if(b[i] != '0' || b[i] == b[i+1])
	    {
            if(k == 0)
                
            {
                cnt1 = b[i] - '0';
                k = 1;
            }
            cnt2++;
	    }
        if(b[i] == '0' || b[i] != b[i+1])
	    {
             int s = strlen(a[cnt1]);
             cnt2--;
             if(b[i] == '0' && b[i+1] != '0')
             {
                 cnt2++;
                 continue;
             }
             cnt2 = cnt2 % s;
             if(b[i] == '0' && b[i+1] == '0')
             {
                printf(" ");
                i++;
             }
             else
                printf("%c", a[cnt1][cnt2]);
             cnt2 = 0;
             k = 0;
	    }
     }
      printf("\n");
   }
   return 0;
  }
  //666660666
  //44444416003334446633111
  //20202202000333003330333