Write a BCPL program that accepts strings from the user and builds them into a binary tree. Whenever the user types * as the input string, your program should print out the entire contents of the tree in alphabetical order, then delete the entire tree, starting again with an empty one.

The program is:

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

typedef struct def_nodo

{char num[500];

 struct def_nodo *izq, *der;

}Tiponodo;

void inserta(Tiponodo **insert, char i[]);

void borra(Tiponodo *p);

void imprime_orden(Tiponodo *p);

int main(void)

{

 char nombre[500];

 Tiponodo *raiz;

 raiz=NULL;

   do{printf("Give me the string you want: ");    

   __fpurge(stdin);

   gets(nombre);

inserta(&raiz,nombre);  

}while(strcmp(nombre,"*")!=0);

 imprime_orden(raiz);

   borra(raiz);

}

void inserta(Tiponodo **insert, char i[])//In this function we insert the new string in our tree

{Tiponodo *avanza, *nuevo;

 avanza=*insert;

     if((nuevo=(Tiponodo *)malloc(sizeof(Tiponodo)))==NULL)

{printf("no hay espacio libre");

  exit(1);

}

     strcpy(nuevo->num,i);

     nuevo->izq=NULL;

     nuevo->der=NULL;

     while(avanza!=NULL)

{

      if(strcmp(avanza->num,i)<0)

 {if(avanza->der!=NULL)

     avanza=avanza->der;

   else

     {avanza->der=nuevo;

       return;

     }

 }

      if(strcmp(avanza->num, i)>=0)

 {if(avanza->izq!=NULL)

     avanza=avanza->izq;

   else

     {avanza->izq=nuevo;

       return;

     }

 }  

}

     avanza=nuevo;

     *insert=avanza;

}

void imprime_orden(Tiponodo *p)//we use this function to print the tree

{if(p!=NULL)

   {imprime_orden(p->izq);

     printf("%s \n", p->num);

     imprime_orden(p->der);

   }

}

void borra(Tiponodo *p)//we use this function to delete the binary tree

{if(p!=NULL)

   {borra(p->izq);

     borra(p->der);

     free(p);

   }

}