今天的一个面试题 - 黑马程序员技术交流社区

class DateDemo
{
public static void main(String[] args)
{
int y1=1989,m1=7,d1=1;
int y2=1990,m2=8,d2=3;
int year=0,count=0,result=0;
//把整年换算成天
for(int i=y1;i<y2;i++)
{
if(i%4==0&&i%100!=0||i%400==0)
year=366;
else
year=365;
count+=year;
}
//终止年已经过的天数加上[起始年,终止年)整年的天数，再减去起始年已经过的天数
System.out.println(count+mathDays(y2,m2,d2)-mathDays(d1,m1,d1));
}
public static int mathDays(int Y,int M,int D)
{
int days=0,count=0;
//判断闰年2月为29天，平年2月为28天，4、6、9、11月为30天，其余月份为31天
if(M==2)
{
if(Y%4==0&&Y%100!=0||Y%400==0)
days=29;
else
days=28;
}
else if(M==4||M==6||M==9||M==11)
days=30;
else
days=31;
//年份小于0，或月份不在[1，12]，或天数不符合前面月份判断条件的，不存在该日期
if(Y<0||(M<1||M>12)||(D<1||D>days))
{
System.out.println("不存在该日期！");
return 0;
}
//计算年份中已经过的天数
for(int i=0;i<=M;i++)
{
if(i==M)
count+=D;
else
count+=days;
}
return count;
}
}

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public class Test {
public static void main(String[] args) {
MyDate d1 = new MyDate(1999, 1, 1);
MyDate d2 = new MyDate(2006, 7, 1);
System.out.println(d1.daysToDate(d2));
}
}
class MyDate {
private static final int[] DAYSINMONTH = {31, 28, 31, 30, 31, 30, 31, 31, 30
,31, 30, 31};
private int year;
private int month;
private int day;
MyDate(int year, int month, int day) {
this.year = year;
this.month = month;
this.day = day;
}
public int daysToDate(MyDate aDate) {
int compareResult = this.compareTo(aDate);
if (compareResult == 0)
return 0;
else if (compareResult > 0)
return aDate.daysToDate(this);
int yearDiff = aDate.year - year;
// same year
if (yearDiff == 0)
return daysToDateInSameYear(aDate);
int totalDaysDiff = (yearDiff - 1) * 365;
for(int i = year + 1; i < aDate.year; i++)
if (isLeapYear(i))
totalDaysDiff++;
// days between this and year-end
totalDaysDiff += daysToDateInSameYear(new MyDate(year, 12, 31));
// days between Jan 1st and aDate
totalDaysDiff = totalDaysDiff + 1 +
new MyDate(aDate.year, 1, 1).daysToDateInSameYear(aDate);
return totalDaysDiff;
}
private boolean isLeapYear(int yr) {
if (yr % 100 != 0 && yr % 4 == 0 || yr % 400 == 0)
return true;
return false;
}
private int compareTo(MyDate aDate) {
if (year == aDate.year) {
if (month == aDate.month) {
if (day == aDate.day)
return 0;
else
return day - aDate.day;
}
else
return month - aDate.month;
}
else
return year - aDate.year;
}
private int daysToDateInSameYear(MyDate aDate) {
int daysDiff = 0;
if (month == aDate.month)
daysDiff = aDate.day - day;
else {
for (int i = month; i <= aDate.month; i++) {
if (i == month) {
daysDiff += DAYSINMONTH[i - 1] - day;
}
else if (i == aDate.month)
daysDiff += aDate.day;
else
daysDiff += DAYSINMONTH[i - 1];
}
}
if (isLeapYear(year)) {
if (month * 100 + day <= 228 &&
aDate.month * 100 + aDate.day > 228)
daysDiff ++;
}
return daysDiff;
}
}

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public static void compare() {
Scanner scanner = new Scanner(System.in);
System.out.print("year 1 :\t");
int year1 = scanner.nextInt();
System.out.print("month 1 :\t");
int month1 = scanner.nextInt();
System.out.print("date 1 :\t");
int date1 = scanner.nextInt();
System.out.print("year 2 :\t");
int year2 = scanner.nextInt();
System.out.print("month 2 :\t");
int month2 = scanner.nextInt();
System.out.print("date 2 :\t");
int date2 = scanner.nextInt();
Calendar d1 = Calendar.getInstance();
d1.set(year1, month1, date1);
Calendar d2 = Calendar.getInstance();
d2.set(year2, month2, date2);
System.out.println(getDaysBetween(d1, d2));
scanner.close();
}
static int getDaysBetween(Calendar d1, Calendar d2) {
if (d1.after(d2)) {
Calendar swap = d1;
d1 = d2;
d2 = swap;
}
int days = d2.get(Calendar.DAY_OF_YEAR) - d1.get(Calendar.DAY_OF_YEAR);
int y2 = d2.get(Calendar.YEAR);
if (d1.get(Calendar.YEAR) != y2) {
d1 = (Calendar) d1.clone();
do {
days += d1.getActualMaximum(Calendar.DAY_OF_YEAR);
d1.add(Calendar.YEAR, 1);
} while (d1.get(Calendar.YEAR) != y2);
}
return days;
}

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#include <stdio.h>
#define leap(y) (y%4==0 && y%100!=0 || y%400==0)
struct d{int y,m,d;};
long days(struct d d1,struct d d2)
{
int mon[2][13]= { {0,31,28,31,30,31,30,31,31,30,31,30,31}, {0,31,29,31,30,31,30,31,31,30,31,30,31} };
int i;
long td=0;
for(i=d1.y;i<d2.y;i++)//
td+=leap(i)?366:365;
for(i=1;i<d1.m;i++)
td-=mon[leap(d1.y)][i];
td-=d1.d-1;
for(i=1;i<d2.m;i++)
td+=mon[leap(d2.y)][i];
td+=d2.d-1;
return td;
}
void main()
{
struct d d1,d2;
long td;
printf("first date:");
scanf("%d-%d-%d",&d1.y,&d1.m,&d1.d);
printf("second date:");
scanf("%d-%d-%d",&d2.y,&d2.m,&d2.d);
td=days(d1,d2);
printf("%ld",td);
}

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