Code genuflect is begged, save the children, it can't write, I want to cry-CodePudding

CodePudding user response:

The first arraylist
The second arraylist
The third use arraylist collections. Sort order
The fourth hashmap

CodePudding user response:

reference 1st floor with ah response:

first arraylist
The second arraylist
The third use arraylist collections. Sort order
The fourth hashmap

Bosses, I need the code

CodePudding user response:

If you really want to learn, well, you should write their own, if only to cope with the homework, I can also help you write one, really don't suggest you directly on the BBS to code

CodePudding user response:

 import Java. Util. *; 
Import the Java. Util. Map. Entry; 

Public class CollectionDemo {

Public static void main (String [] args) {
//TODO automatically generated method stub 
Student st1=new Student (); 
Student st2=new Student (); 
Student st3=new Student (); 
Student [] st={st1, st2, st3}; 
Int count=1; 
CollectionTest01 ct1=new CollectionTest01 (); 
CollectionTest02 ct2=new CollectionTest02 (); 
CollectionTest03 tc3=new CollectionTest03 (); 
CollectionTest04 ct4=new CollectionTest04 (); 
Scanner sc=new Scanner(System.in); 
System. The out. Println (" * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 1 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * "); 
for (int i=0; i <3; I++) {
System. Out. Print (" please enter the first "+" student student id: "+ count); 
St [I] setId (sc), next ()); 
count++; 
} 
Ct1. Set01. Add (st1); 
Ct1. Set01. Add (st2); 
Ct1. Set01. Add (st3); 
For (Student Student: ct1 set01) {
System. The out. Println (student. GetId ()); 
} 
System. The out. Println (" * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 2 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * "); 
Count=1; 
for (int i=0; i <3; I++) {
System. The out. Print (" please enter the first "+ count +" student's name: "); 
St [I] elegantly-named setName (sc), next ()); 
count++; 
} 
Ct2. List02. Add (st1); 
Ct2. List02. Add (st2); 
Ct2. List02. Add (st3); 
For (Student Student: ct2. List02) {
System. The out. Println (student. The getName ()); 
} 
System. The out. Println (" * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * number three * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * "); 
Count=1; 
for (int i=0; i <3; I++) {
System. The out. Print (" please enter the first "+ count +" student score: "); 
St [I] setScores (sc) nextDouble ()); 
count++; 
} 
Tc3. List03. Add (st1); 
Tc3. List03. Add (st2); 
Tc3. List03. Add (st3); 
Tc3. List03. Sort (new Student ()); 
For (Student Student: tc3. List03) {
System. The out. Println (student. GetScores ()); 
} 
System. The out. Println (" * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * the fourth question * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * "); 
Count=1; 
for (int i=0; i <3; I++) {
System. Out. Print (" please enter the first "+" student student id: "+ count); 
St [I] setId (sc), next ()); 
System. The out. Print (" please enter the first "+ count +" student's name: "); 
St [I] elegantly-named setName (sc), next ()); 
Ct4. Map04. Put (st [I] getId (), st [I]); 
count++; 
} 

Set EntrySet=ct4. Map04. EntrySet (); 
For (Entry Et: entrySet) {
System. The out. Print (" student id: "+ et. GetKey () +" "); 
System. The out. Println (" name: "+ et. GetValue (). The getName ()); 
} 
Sc. The close (); 
} 

} 

The class Student implements Comparator {
private String id; 
private String name; 
Private double scores; 

Public String getId () {
return id; 
} 

Public void setId (String id) {
this.id=id; 
} 

Public String getName () {
return name; 
} 

Public void elegantly-named setName (String name) {
this.name=name; 
} 

Public double getScores () {
Return scores; 
} 

Public void setScores (double scores) {
This. Scores=scores; 
} 

@ Override 
Public int the compare (Student Student o1, o2) {
//TODO automatically generated method stub 
Return compare1.c (o1. GetScores (), o2, getScores ()); 
} 

Public int compare1.c (Double o1, o2) Double {
Return to o1.com pareTo (o2); 
} 

} 

The class CollectionTest01 {
Public Set Set01; 

Public CollectionTest01 () {
Set01=new HashSet (a); 
} 
} 

The class CollectionTest02 {
Public List List02; 

Public CollectionTest02 () {
List02=new ArrayList (a); 
} 
} 

The class CollectionTest03 {
Public List List03; 

Public CollectionTest03 () {
List03=new ArrayList (a); 
} 
} 

The class CollectionTest04 {
Public Map Map04; 

Public CollectionTest04 () {
Map04=new HashMap (a); 
} 
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