Determine if two trees are identical

Implement a C program to find the two trees are identical or not.  Two trees are identical when they have same data and arrangement of data is also same.

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct tree{
    int data;
    struct tree *right,*left;
};
struct queue{
    int front,rear;
    int size;
    struct tree**array;
};
struct tree* newNode(int data){
 struct tree *nn = (struct tree*)malloc(sizeof(struct tree));
 nn->data = data;
 nn->left = NULL;
 nn->right = NULL;
 return nn;
}

struct queue* createQueue(int size){
  struct queue* queue = (struct queue*)malloc(sizeof(struct queue));
  queue->size = size;
  queue->front = -1;
  queue->rear = -1;
  queue->array = (struct tree**)malloc(size*sizeof(struct tree*));
  return queue;
}

void enqueue(struct tree *root, struct queue* queue){
    if(queue->rear==queue->size-1)
        return;
    queue->array[++queue->rear] = root;
    if(queue->front == -1)
        queue->front++;
}
 
struct tree* dequeue(struct queue* queue){
    if(queue->front==-1)
        return NULL;
    struct tree *temp = queue->array[queue->front];
    if(queue->front==queue->rear)
    queue->rear = queue->front = -1;
    else
    queue->front++;
    return temp;
}

void insert(struct tree **root, int data, struct queue* queue){
    struct tree *temp = newNode(data);
    if(*root == NULL)
        *root = temp;
    else{
        struct tree *front = queue->array[queue->front];
        if(front->left==NULL)
            front->left = temp;
        else if(front->right == NULL)
            front->right = temp;
        if(front->left!=NULL && front->right!=NULL)
            dequeue(queue);
    }
    enqueue(temp,queue);
}


int identicalTrees(struct tree *a,struct tree *b){
    if(a==NULL && b==NULL){
        return 1;
    }
    else if((a==NULL && b!=NULL)||(a!=NULL && b==NULL)){
        return 0;
    }
    else{
        if((a->data==b->data)&&(identicalTrees(a->left,b->left))&&(identicalTrees(a->right,b->right))){
            return 1;
        }
        else{
            return 0;
        }
    }
}

int main()
{
    struct tree* root1 = NULL,*root2=NULL;
    char ans[3];
    int data,dec;
    struct queue* queue1 = createQueue(50),*queue2=createQueue(50);
 do
 {
     printf("Data to be inserted in 1st tree or 2nd tree?");
     scanf("%d",&dec);
     switch(dec){
        case 1:{printf("Enter the element to be inserted in the 1st tree\n");
                scanf("%d",&data);          
                insert(&root1, data, queue1);
                break;
            
        }
        case 2:{
                printf("Enter the element to be inserted in the 2nd tree\n");
                scanf("%d",&data);          
                insert(&root2, data, queue2);
                break;
        }
     }
    printf("Do you want to insert element?\n");
              scanf("%s",ans);
         } while (strcmp(ans,"yes") ==0);
         if(identicalTrees(root1,root2)){
             printf("Both tree are identical.");
         }
         else{
             printf("Trees are not identical.");
         }
	return 0;
}