新手问题望深度解析迫切 目前初学卡在这里了
public class TestDateSort {
public static void main(String[] args) {
Date[] days = new Date[5];
days[0] = new Date(2006, 5, 4);
days[1] = new Date(2006, 7, 4);
days[2] = new Date(2008, 5, 4);
days[3] = new Date(2004, 5, 9);
days[4] = new Date(2004, 5, 4);
Date d = new Date(2006, 7, 4);
String str = String.valueOf(d);
//str = d.toString();
bubbleSort(days);
for(int i=0; i<days.length; i++) {
System.out.println(days[i]);
}
System.out.println(binarySearch(days, d));
}
public static Date[] bubbleSort(Date[] a){
int len = a.length;
for(int i = len-1;i>=1;i--){
for(int j = 0;j<=i-1;j++){
if(a[j].compare(a[j+1]) > 0){
Date temp = a[j];
a[j]=a[j+1];
a[j+1]=temp;
}
}
}
return a;
}
public static int binarySearch(Date[] days, Date d) {
if (days.length==0) return -1;
int startPos = 0;
int endPos = days.length-1;
int m = (startPos + endPos) / 2;
while(startPos <= endPos){
if(d.compare(days[m]) == 0) return m;
if(d.compare(days[m]) > 0) {
startPos = m + 1;
}
if(d.compare(days[m]) < 0) {
endPos = m -1;
}
m = (startPos + endPos) / 2;
}
return -1;
}
}
class Date {
int year, month, day;
Date(int y, int m, int d) {
year = y; month = m; day = d;
}
public int compare(Date date) {
return year > date.year ? 1
: year < date.year ? -1
: month > date.month ? 1
: month < date.month ? -1
: day > date.day ? 1
: day < date.day ? -1 : 0;
}
public String toString() {
return "Year:Month:Day -- " + year + "-" + month + "-" + day;
}
}
虽然在各位严重也许是很基础的东西但是对于新手来说还是有点迷糊 之前发过帖子 没有贴全部代码 希望这次大哥大姐能给个深度解析 现在正在看数组算法的部分 看的很乱 有点不明白
[解决办法]
你的问题是什么？解释这段代码？
[解决办法]
看着很乱的话，就加个断点单步调试，跟着程序一步一步走，走一遍就不乱了。
public class TestDateSort {
public static void main(String[] args) {
Date[] days = new Date[5];
days[0] = new Date(2006, 5, 4);
days[1] = new Date(2006, 7, 4);
days[2] = new Date(2008, 5, 4);
days[3] = new Date(2004, 5, 9);
days[4] = new Date(2004, 5, 4);
Date d = new Date(2006, 7, 4);
String str = String.valueOf(d);
// str = d.toString();
bubbleSort(days);
for (int i = 0; i < days.length; i++) {
System.out.println(days[i]);
}
System.out.println(binarySearch(days, d));
}
public static Date[] bubbleSort(Date[] a) {//冒泡排序
int len = a.length;
for (int i = len - 1; i >= 1; i--) {
for (int j = 0; j <= i - 1; j++) {
if (a[j].compare(a[j + 1]) > 0) {
Date temp = a[j];
a[j] = a[j + 1];
a[j + 1] = temp;
}
}
}
return a;
}
public static int binarySearch(Date[] days, Date d) {//二分查找
if (days.length == 0)
return -1;
int startPos = 0;
int endPos = days.length - 1;
int m = (startPos + endPos) / 2;
while (startPos <= endPos) {
if (d.compare(days[m]) == 0)
return m;
if (d.compare(days[m]) > 0) {
startPos = m + 1;
}
if (d.compare(days[m]) < 0) {
endPos = m - 1;
}
m = (startPos + endPos) / 2;
}
return -1;
}
}
class Date {
int year, month, day;
Date(int y, int m, int d) {
year = y;
month = m;
day = d;
}
public int compare(Date date) {//我估计你感觉乱的地方应该是这里，这其实就是比较两个Date的大小的方法，前者大就返回1，小就返回-1，相等就返回0
return year > date.year ? 1
: year < date.year ? -1
: month > date.month ? 1
: month < date.month ? -1
: day > date.day ? 1
: day < date.day ? -1 : 0;
//等价于：
/*if (year > date.year)//先比较年
return 1;
else if (year < date.year)
return -1;
else if (month > date.month)//年相等，再比较月
return 1;
else if (month < date.month)
return -1;
else if (day > date.day)//月也相等，在比较日
return 1;
else if (day < date.day)
return -1;
else
return 0;*/
}
public String toString() {
return "Year:Month:Day -- " + year + "-" + month + "-" + day;
}
}