constarcting tree from its preorder,inorder..

[transgalactic2]

i have two arrays which represent the preorder
and inorder traversals in two rows.

i cant see why i get run access memory

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
typedef struct  node node;
struct node{
	int key;
	node* left;
	node* right;
};


 

node* t(char* pre,char* in,int st_pre,int en_pre,int st_in,int en_in); 
int main ()
{
	
	char pre[12]={'a','b','c','d','e','f','g','h','i','j','k','l'};
	char in[12]={'c','b','e','d','f','a','h','g','j','i','l','k'};
	node* root=t(pre,in,0,0,0,0);

	return 0;
}

node* t(char* pre,char* in,int st_pre,int en_pre,int st_in,int en_in)
{
	int i;
	 
     node* root=(node*)malloc(sizeof(node));
	  root->key=pre[st_pre];
	  for(i=0;((i<(int)strlen(pre))&&(pre[st_pre]!=in[i]));i++)
	  {
	  }
	  root->left=t(pre,in,st_pre+1,st_pre+i+1,st_in,i-1);
      root->right=t(pre,in,st_pre+i+1,(int)(strlen(pre)-1),i+1,(int)(strlen(pre)-1));
	  return root;
 
}

[hk_mp5kpdw]

Your t function is infinitely recursive
You do no bounds checking on your int arguments before using them as indexes.
Your char arrays are not strings (aren't null terminated) and you should not therefore be using strlen on them.

[transgalactic2]

i did that
its still gives an empty tree
??

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
typedef struct  node node;
struct node{
	int key;
	node* left;
	node* right;
};


 

node* t(char* pre,char* in,int st_pre,int en_pre,int st_in,int en_in); 
int main ()
{
	
	char pre[13]={'a','b','c','d','e','f','g','h','i','j','k','l','\0'};
	char in[13]={'c','b','e','d','f','a','h','g','j','i','l','k','\0'};
	node* root=t(pre,in,0,0,0,0);

	return 0;
}

node* t(char* pre,char* in,int st_pre,int en_pre,int st_in,int en_in)
{
	int i;
	node* root=(node*)malloc(sizeof(node));
	if (st_pre==en_pre)
		return NULL;
	 
     
	  root->key=pre[st_pre];
	  for(i=0;((i<(int)strlen(pre))&&(pre[st_pre]!=in[i]));i++)
	  {
	  }
	  root->left=t(pre,in,st_pre+1,st_pre+i+1,st_in,i-1);
      root->right=t(pre,in,st_pre+i+1,(int)(strlen(pre)-1),i+1,(int)(strlen(pre)-1));
	  return root;
 
}