Hi, This is my code and it gives Access Violation on test case #1 . Please Help. Its running fine on my system.

#include<stdio.h>
#include<stdlib.h>
struct Tree {
    struct Tree *left;
    struct Tree *right;
    int x;
    int lsize;
};
int insert(struct Tree *root, int x){
    struct Tree *temp =(struct Tree *) malloc(sizeof(struct Tree));
    temp->x = x;
    temp->left = NULL;
    temp->right = NULL;
    temp->lsize=0;
    struct Tree *temp2 = root;
    int flag = 0;
    int count = 0;
    struct Tree *prev = NULL;
    while(temp2!=NULL){
        if(temp2->x>temp->x){
            flag = 0;
            prev = temp2;
            temp2->lsize++;
            temp2 = temp2->left;
        }
        else{
            flag = 1;
            prev = temp2;
            count = count + 1 + prev->lsize;
            temp2 = temp2->right;
        }
    }
    if (flag==0) prev->left = temp;
    else prev->right = temp;
    return count;
}

int main(){
    int n;
    scanf("%d", &n);
    int i = 1;
    int x,y;
    scanf("%d %d", &x, &y);
    struct Tree *root = (struct Tree *) malloc(sizeof(struct Tree));
    root->x = x;
    root->left = NULL;
    root->right = NULL;
    int *ans =(int *)  malloc(n*sizeof(int));
    int j = 0;
    while(j<n){
        ans[j]=0;
        j++;
    }
    ans[0]++;
    while (i<n) {
        scanf("%d %d", &x,&y);
        int k = insert(root,x);
        ans[k]++;
        i++;
    }
    i = 0;
    while(i<n){
        printf("%d \n", ans[i]);
        i++;
    }
    return 0;
}

This code was submitted for C++. It doesn't even compile for C? What might be the issue? It compiles and runs fine on my system.