Tree_order.c

#include<stdio.h>
#include<stdlib.h>
struct tree
{
     char key;
     struct tree *left;
     struct tree *right;
};
typedef struct tree tree;

void create(tree *root);
void preorder(tree *root);
void inorder(tree *root);
void postorder(tree *root);

main()
{
     int c;
     tree* root;
     root=(tree*)malloc(sizeof(tree));
     do
     {
          printf("\n1. Create ");
          printf("\n2. Pre-order ");
          printf("\n3. In-Order ");
          printf("\n4. Post-order ");
          printf("\n5. Exit ");
          printf("\nEnter Your Choice ::");
          scanf("%d",&c);

          switch(c)
          {
          case 1:
               create(root);
               break;
          case 2:
               preorder(root);
               break;
          case 3:
               inorder(root);
               break;
          case 4:
               postorder(root);
               break;
          }
     }while(c!=5);
}

void create(tree *root)
{
     char u;
     fflush(stdin);
     printf("\nKey ::");
     scanf("%c",&root->key);
     fflush(stdin);
     printf("\nDo you want to add left child of %c ::",root->key);
     scanf("%c",&u);
     if(u=='y' || u=='Y')
     {
          root->left=(tree*)malloc(sizeof(tree));
          create(root->left);
     }
     else
          root->left=NULL;
     fflush(stdin);
     printf("\nDo you want to add right child of %c ::",root->key);
     scanf("%c",&u);
     if(u=='y' || u=='Y')
     {
          root->right=(tree*)malloc(sizeof(tree));
          create(root->right);
     }
     else
     {
          root->right=NULL;
     }
}

void preorder(tree *root)
{
     if(root!=NULL)
     {
          printf("%c",root->key);
          preorder(root->left);
          preorder(root->right);
     }
}

void inorder(tree *root)
{
     if(root!=NULL)
     {
          inorder(root->left);
          printf("%c",root->key);
          inorder(root->right);
     }
}

void postorder(tree *root)
{
     if(root!=NULL)
     {
          postorder(root->left);
          postorder(root->right);
          printf("%c",root->key);
     }
}