C Programming :: Control Instructions - Discussion

#include <stdio.h>
int main()
{
       int ones, twos, threes, others;
       int c;
       ones = twos = threes = others = 0;
       while ((c = getchar ()) != EOF)
       {
                  switch (c)
                  {
                     case '1': ++ones;
                     case '2': ++twos;
                     case '3': ++threes;
                                       break;
                     default: ++others;
                                       break;
                  }
       }
       printf ("%d  %d", ones, others);
       return 0;
    }