Implementing Student information Management system with list collection

public class Studentinformation {


Scanner input=new Scanner (system.in);

Arraylist<student> list=new arraylist<student> ();

public void Start () {

System.out.println ("function menu is as follows:");
System.out.println ("1. Input student Information");
System.out.println ("2. Inquiry student information According to school number");
System.out.println ("3. Modify student Information");
System.out.println ("4. Delete Student information according to school number");
System.out.println ("5. Statistical student Average test results");
System.out.println ("6. Exit system");
System.out.println ("-------------------");
SYSTEM.OUT.PRINTLN ("Please choose:");

String Index=input.next ();

if ("1". Equals (index)) {
Input Student Information
Save ();
}else if ("2". Equals (index)) {
Check student information according to school number
Search ();
}else if ("3". Equals (index)) {
Modify Student Information
Modify ();
}else if ("4". Equals (index)) {
Delete Student information according to school number
Remove ();
}else if ("5". Equals (index)) {
Average test scores of statistical trainees
Average ();
}else if ("6". Equals (index)) {
Exit system
System.exit (0);
}else{
SYSTEM.OUT.PRINTLN ("Input error, please re-enter.") ");
}

Start ();

}


/**
* Average scores of students in statistical examinations
*/
private void average () {
int sum=0;
for (int i=0;i<list.size (); i++) {
Student S=list.get (i);
Sum+=s.getscore ();
}
float ave=sum/list.size ();
System.out.println ("The average student score is:" +ave);

}


/**
* Delete Student information according to school number
*/
private void Remove () {
System.out.println ("Enter the student number to be deleted:");
String Num=input.next ();

for (int i = 0; i < list.size (); i++) {
Student S=list.get (i);
if (S.getstudentnum (). Equals (num)) {
List.remove (s);
System.out.println ("delete succeeded.") ");
}
}

}


/**
* Revise student information
*/
private void Modify () {
System.out.println ("Enter the student number to be modified:");
String Num=input.next ();

for (int i = 0; i < list.size (); i++) {
Student S=list.get (i);
if (S.getstudentnum (). Equals (num)) {


System.out.println ("Enter new student Name:");
String Name=input.next ();
System.out.println ("Enter new student Age:");
int Age=input.nextint ();
System.out.println ("Enter new student score:");
int Score=input.nextint ();

S.setname (name);
S.setage (age);
S.setscore (score);

SYSTEM.OUT.PRINTLN ("modified successfully.") ");

}
}


}




/**
* Inquiry student Information according to the school number
*/
private void Search () {
System.out.println ("Please enter the school number:");
String Num=input.next ();


Student S=null;
for (Student stu:list) {


if (Stu.getstudentnum (). Equals (num)) {
S=stu;
Break
}

}
if (s!=null) {
System.out.println ("School Number:" +s.getstudentnum ());
System.out.println ("Name:" +s.getname ());
System.out.println ("Age:" +s.getage ());
System.out.println ("Score:" +s.getscore ());
}else{
System.out.println ("The school number does not exist.") ");
}

/*
Student S=null;
for (int i=0;i<list.size (); i++) {
S=list.get (i);
if (S.getstudentnum (). Equals (num)) {

System.out.println ("School Number" + "\t\t" + "name" + "\t\t" + "age" + "\t\t" + "achievement");

StringBuffer sb=new StringBuffer ();
Sb.append (S.getstudentnum ()). Append ("\t\t"). Append (S.getname ()). Append ("\t\t"). Append (S.getage ()). Append ("\ t \ t "). Append (S.getscore ());
Sb.append (S.getstudentnum () + "\t\t" +s.getname () + "\t\t" +s.getage () + "\t\t" +s.getscore ());
String str=sb.tostring ();
System.out.println (str);
}else {
System.out.println ("The school number does not exist.") ");
}
}*/

}


/**
* Input Student Information
*/
private void Save () {

System.out.println ("Please enter the school number:");
String Num=input.next ();
System.out.println ("Please enter Name:");
String Name=input.next ();
System.out.println ("Please enter Age:");
int Age=input.nextint ();
System.out.println ("Please enter the score:");
int Score=input.nextint ();

Student s=new Student ();
S.setstudentnum (num);
S.setname (name);
S.setage (age);
S.setscore (score);

List.add (s);
SYSTEM.OUT.PRINTLN ("Information entry success.") ");

}

}