changing my python code to c++?

edit

def subalg_fun(self):

    cap = cv2.VideoCapture(1)
    time.sleep(2)


    _, first_frame = cap.read()
    first_gray = cv2.cvtColor(first_frame, cv2.COLOR_BGR2GRAY)
    first_gray = cv2.GaussianBlur(first_gray, (5, 5), 0)
    while True:


        _, frame = cap.read()
        gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

        gray_frame = cv2.GaussianBlur(gray_frame, (5, 5), 0)
        sub_image = cv2.subtract(first_gray, gray_frame)
        thresh = cv2.threshold(sub_image , 20, 255, cv2.THRESH_BINARY)[1]
        thresh = cv2.dilate(thresh, None, iterations=3)
        result = not np.any(thresh)
        cv2.imshow("Frame", frame)
        cv2.imshow("sub", sub_image)
        if result is True:

            print("nothing:",nth)


        else:
            print("difff:",diff)

        # cv2.imshow("difference", difference)
        key = cv2.waitKey(30)
        if key == 27:
            break

i converted the above code from python to c++ successfully but my problem is "result = not np.any(thresh)" here we use numpy to find the difference what is alternate solution for c++