实现一个电子日历，输入一个日期，判断其正确性并输出下一天。对闰年和各月份做了详细分析。代码清晰，对学习if语句和case语句很有帮助。-To achieve an electronic calendar, enter a date, to determine its correctness and output the next day. On the leap year and has done a detailed analysis of the month. Code is clear,