parser algorithm

#include<stdlib.h>
#include<stdio.h>
#include<string.h>

struct bin_tree {
char data;
struct bin_tree * right, * left;
};
typedef struct bin_tree node;

void insert(node ** tree, char val)
{
    node *temp = NULL;
    if(!(*tree))
    {
        temp = (node *)malloc(sizeof(node));
        temp->left = temp->right = NULL;
        temp->data = val;
        *tree = temp;
        return;
    }

    if(val < (*tree)->data)
    {
        insert(&(*tree)->left, val);
    }
    else if(val > (*tree)->data)
    {
        insert(&(*tree)->right, val);
    }

}

void print_preorder(node * tree)
{
    if (tree)
    {
        printf("\n%c",tree->data);
        print_preorder(tree->left);
        print_preorder(tree->right);
    }

}

void print_inorder(node * tree)
{
    if (tree)
    {
        print_inorder(tree->left);
        printf("\n%c",tree->data);
        print_inorder(tree->right);
    }
}

void print_postorder(node * tree)
{
    if (tree)
    {
        print_postorder(tree->left);
        print_postorder(tree->right);
        printf("\n%c",tree->data);
    }
}

void deltree(node * tree)
{
    if (tree)
    {
        deltree(tree->left);
        deltree(tree->right);
        free(tree);
    }
}


void main()
{
    node *root;
    node *tmp;

    root = NULL;

    char str1[100];
    char newString[10][10];
    int i,j,k,temp,m;
    char newChar[100];

    printf("\nUniversity of petroleum and energy studies.:\n");
    printf("\n Input a string for which you want to perform Tockenization : ");
    fgets(str1, sizeof str1, stdin);

    j=0;
    temp=0;
    m = 0;
    for(i=0;i<=(strlen(str1));i++){
        if(str1[i]==' '||str1[i]=='\0')
        {
            newString[temp][j]='\0';
            temp++;
            j=0;
        }
        else
        {
            newString[temp][j]=str1[i];
            newChar[m] = str1[i];
            m++;
            j++;
        }
    }
    printf("\n tokens after split by space are :\n");
    for(i=0;i < temp;i++)
        printf(" %s\n",newString[i]);

    for(i=0;i < m;i++){
        //printf(" %c\n",newChar[i]);
        insert(&root, newChar[i]);
    }
    /*

    insert(&root, 'H');
    insert(&root, 'E');
    insert(&root, 'L');
    insert(&root, 'L');
    insert(&root, 'O');
*/
    printf("\nPre Order Display");
    print_preorder(root);

    printf("\nIn Order Display");
    print_inorder(root);

    printf("\nPost Order Display");
    print_postorder(root);

    deltree(root);
}