计算每个数字，空白字符（空白，制表符，换行符）和所有其他字符的出现次数。

#include <stdio.h>  

   int main() 
   {  
       int c, nwhite= 0, nother= 0;  
       int ndigit[10];  

       for (int i = 0; i < 10; ++i)  
           ndigit[i] = 0;  

       while ((c = getchar()) != EOF)  {
           if (c >= '0' && c <= '9')  
               ++ndigit[c-'0'];  
           else if (c == ' ' || c == '/n' || c == '/t')  
               ++nwhite;  
           else  
               ++nother;  
  }
       printf("digits =");  
       for (int i = 0; i < 10; ++i)  
           printf(" %d", ndigit[i]);  
       printf(", white space = %d, other = %d/n", nwhite, nother);  
   }