Hello Reddy JS,
Thank you for contacting National Instruments.
Please follow the link below to a Visual C++ Example Program which generates a continuous pulse train.
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3DFFB56A4E034080020E74861&p_node=DZ52328&p_source=External
Let me know if you have any further questions.
Sincerely,
Sean C.
Applications Engineer
National Instruments