一个用来计算每年1月1号星期几的c小程序！实现比较简单，其实就是计算闰年的小程序，不过小程序可能有点小bug，希望大家包含！-one used to calculate the annual January 1 several weeks of c small program! Achieving a relatively simple calculation of leap year is actually a small, but a small program might have a small bug, we hope that contain!