if(ch==5)/*menu to sort list*/
      {
               node *t,q;
               int i,j,n=0;
               t=first;/*first node*/
               while(t!=NULL)
               {
                             t=t->next;
                             n++;
                             }

               for(i=0; i<n; i++)
               {
                        for(j=0; j<n-i; i++)
                        {
                                 if(t->next!=NULL){
                                 if((t->age)>((t->next)->age)){
                                 q=*t;
                                 *t=*(t->next);
                                 *(t->next)=q;}
                                 }
                        }
               }