Introduction - If you have any usage issues, please Google them yourself
The processor (Preprocessor) 1. With preprocessing directives# create a profile for a resource declare a constant, to indicate that 1 years how many seconds (ignoring a leap year problem) Create a profile for a resource# SECONDS_PER_YEAR (60* 60** 365) UL 24 I want to see a few things: Create a profile for a resource# 1). The basic grammar knowledge (for example: can t with semicolon, the use of brackets, etc.) 2). Know the processor will be in your calculation constant expression value, so, write you is how to calculate the direct a year rather than how many seconds to figure out the actual value, is the more clear and no cost. 3). To realize this expression will make a 16-bit machine integer overflow-so to use long integer symbols, tell the compiler L the constant is yes long integer. 4). If you in your expression used UL (said unsigned long integer), then you have a good starting point. Remember, the first impression is very important.