C language topic SMS tariff

The reference program has been sent to you. Generally, it is not successful to paste other people's programs directly, because there is no separate GSM module, and the single chip microcomputer module is different. The program written by others may not be suitable for you, others may have it, so you can't get it here. You mainly need to look at the important functions in the reference program, such as sending function and accepting interrupt function. . . Then debug slowly, don't expect to realize all the functions at once. For example, you should debug the connection with GSM module first, send it an AT, and see if it returns OK to you, and then proceed to the next step. (Of course, if you use the upper computer to debug now, you must see whether your single-chip microcomputer has accepted what you sent and whether your function of accepting interrupts is correct).