C standard must use int. As for each compiler and development environment, it may have its own implementation, but it is absolutely correct to return int. If it is void, some compilers may think it is right and some think it is wrong, so it is not safe. It is recommended that the main function be written in the following standard format:

int main(int argc，char *argv[])

{

/* program code */

Returns 0; /* It is preferable to return an integer value, although some compilers will return zero */

}