how to resize camera with screen resolution in unity code example

Example 1: unity camera fit

[ExecuteInEditMode]
[RequireComponent(typeof(Camera))]
public class MatchWidth : MonoBehaviour {

    // Set this to the in-world distance between the left & right edges of your scene.
    public float sceneWidth = 10;

    Camera _camera;
    void Start() {
        _camera = GetComponent<Camera>();
    }

    // Adjust the camera's height so the desired scene width fits in view
    // even if the screen/window size changes dynamically.
    void Update() {
        float unitsPerPixel = sceneWidth / Screen.width;

        float desiredHalfHeight = 0.5f * unitsPerPixel * Screen.height;

        camera.orthographicSize = desiredHalfHeight;
    }
}

Example 2: unity camera fit

public float horizontalFoV = 90.0f;

// for perspective cam

void Update() {
   float halfWidth = Mathf.Tan(0.5f * horizontalFoV * Mathf.Deg2Rad);

   float halfHeight = halfWidth * Screen.height / Screen.width;

   float verticalFoV = 2.0f * Mathf.Atan(halfHeight) * Mathf.Rad2Deg;

   camera.fieldOfView = verticalFoV;
}