#include  <stdio.h>
  #include  <string.h>
  fun(char *w,int n)
   {char t,*s1,*s2;
    s1=w;s2=w+n-1;
    while(s1<s2){t=*s1++;*s1=*s2--;*s2=t;}}
  main()
{char *p;
  p="1234567";
  fun(p,strlen(p));
  puts(p);}