iOS Objective-C 代码：判断传入年和月，返回对应月份的最后一天

"你可以使用NSCalendar和NSDateComponents来实现这个功能。下面是一个示例代码：\n\nobjectivec\n// 获取当前日期\nNSDate *currentDate = [NSDate date];\n\n// 创建一个日历对象\nNSCalendar *calendar = [NSCalendar currentCalendar];\n\n// 获取当前日期的年、月、日组成部分\nNSDateComponents *currentComponents = [calendar components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:currentDate];\nNSInteger currentYear = [currentComponents year];\nNSInteger currentMonth = [currentComponents month];\nNSInteger currentDay = [currentComponents day];\n\n// 创建选中日期的年、月、日组成部分\nNSDateComponents *selectedComponents = [[NSDateComponents alloc] init];\n[selectedComponents setYear:2023];\n[selectedComponents setMonth:7];\n[selectedComponents setDay:28];\n\n// 获取选中日期的年、月、日组成部分\nNSInteger selectedYear = [selectedComponents year];\nNSInteger selectedMonth = [selectedComponents month];\nNSInteger selectedDay = [selectedComponents day];\n\n// 判断当前日期和选中日期的年份和月份是否相同\nif (currentYear == selectedYear && currentMonth == selectedMonth) {\n // 如果相同，返回当前日期的日份\n NSLog(@"选中日期的日份：%ld", (long)currentDay);\n} else {\n // 如果不相同，计算选中日期所在月的最后一天\n NSRange daysRange = [calendar rangeOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitMonth forDate:[calendar dateFromComponents:selectedComponents]];\n NSInteger lastDay = daysRange.length;\n NSLog(@"选中日期所在月的最后一天：%ld", (long)lastDay);\n}\n\n\n请注意，这里的示例代码假设你已经将其放置在合适的上下文中，并且你可能需要根据你的实际需求进行一些修改。\