strcpy(buf1, "my_com_id_%d", j)
First I want to place value of i into "my_id_1" like so and copy to buf. And do the same thing in second line the code. Now I want to join both buf and buf1 so it will give me a new string "my_id_1_my_com_id_2".
How do you do this kind of stuff and joining two strings in C?