What is the Problem in this Binary Search Tree code?

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

//Biinary Search Tree
typedef struct NODE
{
int data;
struct NODE * lchild, *rchild;
}node;

node * add(node * root, int n)
{
node *temp, *parent, *current;
temp=(node *)malloc(sizeof(node));
temp->data=n;
temp->lchild=NULL;
temp->rchild=NULL;

int opt=1;
if(root==NULL)
{
    root=temp;
    opt=0;
}

else
{
    current=root;
    parent=NULL;
}

while(opt)
{
    parent=current;

    if(n<(parent->data))
    {
        current=(parent->lchild);
        if(current==NULL)
        {
            current=temp;
            opt=0;
        }

    }

    else if(n>parent->data)
    {
        current=(parent->rchild);
        if(current==NULL)
        {
            current=temp;
            opt=0;
        }
    }
}

return root;
}

//Given a binary tree, print its nodes in in-order
void printInorder(node * root)
{
if(root==NULL)
{
return;
}
printInorder(root->lchild);
printf("%d ", root->data);
printInorder(root->rchild);
}

int main()
{
node *root=NULL;
int opt, x;
do
{
printf("\nWELCOME!!!\nEnter 1 to ADD node\nEnter 2 for IN-ORDER\nEnter 3 for PRE-ORDER\nEnter 4 for POST-ORDER\nEnter 5 to exit\n");
scanf("%d", &opt);
switch(opt)
{
case 1 : printf(“Enter the Number to add\n”);
scanf("%d", &x);
root=add(root, x);
break;
case 2 : printInorder(root);
break;
default :printf(“This option is not yet prepared\n”);
break;
}
}while(opt!=5);

return 0;
}

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