void reverse (char *str)
{
    char * end=str;
    char temp;
    while(*end)
    {
        ++end;
    }
    --end;
    cout<<str<<endl;
    cout<<end<<endl;
    while(str<end){
        temp=*str;
        *str++=*end;
        *end--=temp;
    }


}
int main()
{
    char s[]="abcdef";
    char * str=s;
    reverse(str);
    cout<<str<<endl;
}
// reverse string;