What is the difference between these two code snippet? Both of them returns a different results without raising any error.

    int arr[] = { 15, 10, 5 };
    sort(arr,arr+3);
    for(auto it : arr){
        std::cout<<it<<" "; // 5 10 15
    }

    int arr[] = { 15, 10, 5 };
    sort(&arr[0],&arr[2]);
    for(auto it : arr){
        std::cout<<it<<" "; // 10 15 5
    }

Can anyone please explain??!

I suddenly encounter this problem using this code, it is not sorting properly.

    int arr[] = { 15, 10, 5 };
    sort(&arr[0],&arr[2]);
    for(auto it : arr){
        std::cout<<it<<" ";
    }

Then I searched for the right way to this, which is

    int arr[] = { 15, 10, 5 };
    sort(arr,arr+3);
    cout<<endl;
    for(auto it : arr){
        std::cout<<it<<" ";
    }