java:prg suivant me donne aucun output

Question

Bonjour, 

import java.io.*;
public class StuDetail 
{
  int RollNo;
}
class StudMarks extends StuDetail
{
	float sub1;
	float sub2;
	float sub3;
	float TotalMarks;
	
	void getData()
	{
		System.out.println("
Recording Entry");
		try
		{
			BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
			String sRNo,sSub1,sSub2,sSub3;
			
			System.out.println("Enter Roll No:");
			System.out.flush();
			sRNo=obj.readLine();
			RollNo=Integer.parseInt(sRNo);
			
			System.out.println("Enter Marks for Subject 1:");
			System.out.flush();
			sSub1=obj.readLine();
			sub1=Float.parseFloat(sSub1);
			
			System.out.println("Enter Marks for Subject 2:");
			System.out.flush();
			sSub2=obj.readLine();
			sub2=Float.parseFloat(sSub2);
			
			System.out.println("Enter Marks for Subject 3:");
			System.out.flush();
			sSub3=obj.readLine();
			sub3=Float.parseFloat(sSub3);
			
			TotalMarks=sub1+sub2+sub3;
		}
		catch(Exception e)
		{}	
		}
	    void display()
	    {
	    	System.out.println("
Displaying Record");
	    	System.out.println("Roll No:"+RollNo);
	    	System.out.println("Subject 1:"+sub1);
	    	System.out.println("Subject 1:"+sub2);
	    	System.out.println("Subject 1:"+sub3);
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	    void TotalMarks()
	    {
	    	System.out.println("
Displaying Record");
	    	System.out.println("Roll No:"+RollNo);	
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	}
class StudentDatabase
{
 public static void main(String []args)
 {
	 System.out.println("
======STUDENT DATABASE=====
");
	 
	 float HighMark_sub1;
	 float HighMark_sub2;
	 float HighMark_sub3;
	 float StudHightMark;
	 int No_of_stud=3,choice;
	 String str;
	 char c;
	 
	 try
	 {
		BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
		System.out.print("
Enter number of students:");
		System.out.flush();
		str=obj.readLine();
		No_of_stud=Integer.parseInt(str);
		StudMarks SMobj[]=new StudMarks[No_of_stud];
		
		while(true)
		{
			System.out.println("
Choose your choice....");
			System.out.println("1)PASS ENTRY");
			System.out.println("2)DISPLAY ALL RECORDS");
			System.out.println("3)DISPLAT TOTAL MARKS for all students");
			System.out.println("4)DISPLAT HIGHEST MARKS in each subject");
			System.out.println("5 DISPLAY student who recived highest total marks");
			System.out.println("6 Exit");
			System.out.println("ENTER YOUR CHOICE:");
			System.out.flush();
			str=obj.readLine();
			choice=Integer.parseInt(str);
			
			switch(choice)
			{
			 case 1:
				 for(int i=0; i<No_of_stud; i++)
					 SMobj[i].getData();
				 break;
			 case 2:
				 for(int i=0; i<No_of_stud; i++)
					 SMobj[i].display();
				 break;
			 case 3:
				 for(int i=0; i<No_of_stud; i++)
					 SMobj[i].TotalMarks();
				 break;
			 case 4:break;
			 case 5:break;
			 case 6:System.out.println("
Thanks for visting.....");
			 System.exit(1);	 
			}
		} 
	 }
	 catch(Exception e)
	 {}
 }
}

en exécutant mon prg,rien se passe ,aidez moi svp

Configuration: Windows 7 / Firefox 12.0

KX · Answer

La méthode main doit être dans une classe public sinon elle ne sera pas exécutée.

domxaline · Answer

ok j'ai comme vs avez dit
affiche le resultat suivante:

======STUDENT DATABASE=====


Enter number of students:5

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
1

après enter your choice:
j'ai tapé le chiffre 1
et j'essaie rentrer le data mais ça se passe rien,aidez moi svp

domxaline · Answer

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class StudentDatabase 
{
	public static void main(String []args)
	 {
		 System.out.println("
======STUDENT DATABASE=====
");
		 
		 float HighMark_sub1;
		 float HighMark_sub2;
		 float HighMark_sub3;
		 float StudHightMark;
		 int No_of_stud=3,choice;
		 String str;
		 char c;
		 
		 try
		 {
			BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
			System.out.print("
Enter number of students:");
			System.out.flush();
			str=obj.readLine();
			No_of_stud=Integer.parseInt(str);
			StudMarks SMobj[]=new StudMarks[No_of_stud];
			
			while(true)
			{
				System.out.println("
Choose your choice....");
				System.out.println("1)PASS ENTRY");
				System.out.println("2)DISPLAY ALL RECORDS");
				System.out.println("3)DISPLAT TOTAL MARKS for all students");
				System.out.println("4)DISPLAT HIGHEST MARKS in each subject");
				System.out.println("5 DISPLAY student who recived highest total marks");
				System.out.println("6 Exit");
				System.out.println("ENTER YOUR CHOICE:");
				System.out.flush();
				str=obj.readLine();
				choice=Integer.parseInt(str);
				
				switch(choice)
				{
				 case 1:
					 for(int i=0; i<No_of_stud; i++)
					 SMobj[i] = new SMobj(i);
					 SMobj[i].getData();
					 break;
				 case 2:
					 for(int i=0; i<No_of_stud; i++)
						 SMobj[i].display();
					 break;
				 case 3:
					 for(int i=0; i<No_of_stud; i++)
						 SMobj[i].TotalMarks();
					 break;
				 case 4:break;
				 case 5:break;
				 case 6:System.out.println("
Thanks for visting.....");
				 System.exit(1);	 
				}
			} 
		 }
		 catch(Exception e)
		 { e.printStackTrace();}
	 }
}

j'ai erreur suivantes
Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
	SMobj cannot be resolved to a type
	i cannot be resolved to a variable

	at StudentDatabase.main(StudentDatabase.java:44)

lignes 44 est le suivant:
SMobj[i] = new SMobj(i);

domxaline · Answer

switch(choice)
 {
   case 1:
   for(int i=0; i<No_of_stud; i++)
   {
     SMobj[i] = new SMobj(i);
     SMobj[i].getData();
     break;
  }

j'ai essayé,j'ai erreur suivante:
Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	SMobj cannot be resolved to a type

new SMobj(i);

domxaline · Answer

Tu ne peux mettre new SMobj(i) que si tu as un constructeur SMobj(int n), ce qui n'est probablement pas le cas... 

alors quel est la solution,svp

domxaline · Answer

j'ai corrigé mais le résultat n'es pas bon

import java.io.*;
public class StuDetail 
{
  int RollNo;
}
class StudMarks extends StuDetail
{
	float sub1;
	float sub2;
	float sub3;
	float TotalMarks;
	StudMarks(int SMobj)
	{
		
	}
	
	void getData()
	{
		System.out.println("
Recording Entry");
		try
		{
			BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
			String sRNo,sSub1,sSub2,sSub3;
			
			System.out.println("Enter Roll No:");
			System.out.flush();
			sRNo=obj.readLine();
			RollNo=Integer.parseInt(sRNo);
			
			System.out.println("Enter Marks for Subject 1:");
			System.out.flush();
			sSub1=obj.readLine();
			sub1=Float.parseFloat(sSub1);
			
			System.out.println("Enter Marks for Subject 2:");
			System.out.flush();
			sSub2=obj.readLine();
			sub2=Float.parseFloat(sSub2);
			
			System.out.println("Enter Marks for Subject 3:");
			System.out.flush();
			sSub3=obj.readLine();
			sub3=Float.parseFloat(sSub3);
			
			TotalMarks=sub1+sub2+sub3;
		}
		catch(Exception e)
		{}	
		}
	    void display()
	    {
	    	System.out.println("
Displaying Record");
	    	System.out.println("Roll No:"+RollNo);
	    	System.out.println("Subject 1:"+sub1);
	    	System.out.println("Subject 1:"+sub2);
	    	System.out.println("Subject 1:"+sub3);
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	    void TotalMarks()
	    {
	    	System.out.println("
Displaying Record");
	    	System.out.println("Roll No:"+RollNo);	
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	}




import java.io.BufferedReader;
import java.io.InputStreamReader;
public class StudentDatabase 
{
	public static void main(String []args)
	 {
		 System.out.println("
======STUDENT DATABASE=====
");
		 
		 float HighMark_sub1;
		 float HighMark_sub2;
		 float HighMark_sub3;
		 float StudHightMark;
		 int No_of_stud=3,choice;
		 String str;
		 char c;
		 
		 try
		 {
			BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
			System.out.print("
Enter number of students:");
			System.out.flush();
			str=obj.readLine();
			No_of_stud=Integer.parseInt(str);
			StudMarks SMobj[]=new StudMarks[No_of_stud];
			while(true)
			{
				System.out.println("
Choose your choice....");
				System.out.println("1)PASS ENTRY");
				System.out.println("2)DISPLAY ALL RECORDS");
				System.out.println("3)DISPLAT TOTAL MARKS for all students");
				System.out.println("4)DISPLAT HIGHEST MARKS in each subject");
				System.out.println("5 DISPLAY student who recived highest total marks");
				System.out.println("6 Exit");
				System.out.println("ENTER YOUR CHOICE:");
				System.out.flush();
				str=obj.readLine();
				choice=Integer.parseInt(str);
				
				switch(choice)
				{
				 case 1:
					 for(int i=0; i<No_of_stud; i++)
					 {
					 SMobj[i] = new StudMarks(i);
					 SMobj[i].getData();
					 }
					 break;
				 case 2:
					 for(int i=0; i<No_of_stud; i++)
						 {
						 SMobj[i] = new StudMarks(i);
						 SMobj[i].display();
						 }
					 break;
				 case 3:
					 for(int i=0; i<No_of_stud; i++)
					 {
						 SMobj[i] = new StudMarks(i);
						 SMobj[i].TotalMarks();
					 }
					 break;
				 case 4:break;
				 case 5:break;
				 case 6:System.out.println("
Thanks for visting.....");
				 System.exit(1);	 
				}
			} 
		 }
		 catch(Exception e)
		 { e.printStackTrace();}
	 }
}

======STUDENT DATABASE=====


Enter number of students:3

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
1

Recording Entry
Enter Roll No:
10
Enter Marks for Subject 1:
3
Enter Marks for Subject 2:
4
Enter Marks for Subject 3:
5

Recording Entry
Enter Roll No:
11
Enter Marks for Subject 1:
2
Enter Marks for Subject 2:
4
Enter Marks for Subject 3:
5

Recording Entry
Enter Roll No:
12
Enter Marks for Subject 1:
6
Enter Marks for Subject 2:
7
Enter Marks for Subject 3:
8

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
2

Displaying Record
Roll No:0
Subject 1:0.0
Subject 1:0.0
Subject 1:0.0
Total Marks:0.0

Displaying Record
Roll No:0
Subject 1:0.0
Subject 1:0.0
Subject 1:0.0
Total Marks:0.0

Displaying Record
Roll No:0
Subject 1:0.0
Subject 1:0.0
Subject 1:0.0
Total Marks:0.0

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
3

Displaying Record
Roll No:0
Total Marks:0.0

Displaying Record
Roll No:0
Total Marks:0.0

Displaying Record
Roll No:0
Total Marks:0.0

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:

domxaline · Answer

methode void display et void TotalMarks fonctionnent pas
aidez moi svp

void display()
	    {
	    	System.out.println("
Displaying Record");
	    	System.out.println("Roll No:"+RollNo);
	    	System.out.println("Subject 1:"+sub1);
	    	System.out.println("Subject 1:"+sub2);
	    	System.out.println("Subject 1:"+sub3);
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	    void TotalMarks()
	    {
	    	System.out.println("
Displaying Record");
	    	System.out.println("Roll No:"+RollNo);	
	    	System.out.println("Total Marks:"+TotalMarks);
	    }

domxaline · Answer

La vérité est ailleurs...

viens d' où, expliquez moi svp

domxaline · Answer

case 2: 
      for(int i=0; i<No_of_stud; i++) 
       { 
       SMobj[i] = new StudMarks(i); 
       SMobj[i].display(); 
       } 
      break; 

je les appelle ici vs voyes

domxaline · Answer

case 2:
	 System.out.printf("#%d
",No_of_stud);
	 for(int i=0; i<No_of_stud; i++)
	{
	  SMobj[i] = new StudMarks(i);
	  SMobj[i].display();
	}
	 break;

j'avais fait comme vs avez dit mais le résultat est le suivant
Enter number of students:2

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
1

Recording Entry
Enter Roll No:
1
Roll No:1
Enter Marks for Subject 1:
11
Enter Marks for Subject 2:
12
Enter Marks for Subject 3:
13
TotalMarks36.0

Recording Entry
Enter Roll No:
2
Roll No:2
Enter Marks for Subject 1:
21
Enter Marks for Subject 2:
23
Enter Marks for Subject 3:
25
TotalMarks69.0

Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
2
#2

Displaying Record
Roll No:0
Subject 1:0.0
Subject 2:0.0
Subject 3:0.0
Total Marks:0.0

Displaying Record
Roll No:0
Subject 1:0.0
Subject 2:0.0
Subject 3:0.0
Total Marks:0.0

normalement il doit s'afficher comme suivant mais s'affiche pas pourquoi?
Displaying Record
Roll No:1
Subject 1:11.0
Subject 2:12.0
Subject 3:13.0
Total Marks:36.0

Displaying Record
Roll No:2
Subject 1:21.0
Subject 2:23.0
Subject 3:25.0
Total Marks:69.0

domxaline · Answer

je comprend toujours pas,excusez moi svp
alors quel est la solution svp

domxaline · Answer

j'ai fait comme vous m'avais conseillé

case 1:
	 for(int i=0; i<No_of_stud; i++)
	 {
	   //SMobj[i] = new StudMarks(i);
	   SMobj[i].getData();
	 }
	 break;
	 case 2:
	 System.out.printf("#%d
",No_of_stud);
	 for(int i=0; i<No_of_stud; i++)
	{
	  SMobj[i] = new StudMarks(i);
	  SMobj[i].display();
	}
       break;

mais il plante pour la premier choice
ENTER YOUR CHOICE:
1
java.lang.NullPointerException
	at StudentDatabase.main(StudentDatabase.java:45)

domxaline · Answer

mer
merci beaucoup,ça marche

domxaline · Answer

on a réussi pour display et total marks

maintenant je besoin vos conseil pour
-highest marks pour chaque sujet, et
-élève qui a reçu highest marks

pouvez vs me donnez quelque idées svp

domxaline · Answer

j'ai ces variables à ma disposition
		 float HighMark_sub1;
		 float HighMark_sub2;
		 float HighMark_sub3;
		 float StudHightMark;
il faut que je commence avec for et if
for(int i=0;i<3;i++)
{
    if( )
   {
    
    }
}
après j'hésite aidez moi

domxaline · Answer

il n'y a personne pour m'aider

domxaline · Answer

void HighestMarks()
	    {
	    	for(int i=0;i<3;i++)
	    	{
	    		if (sub1>max1)
	    		{
	    			max1=sub1;
	    		}
	    		if (sub2>max2)
	    		{
	    			max2=sub2;
	    		}
	    		if (sub3>max3)
	    		{
	    			max3=sub3;
	    		}
	    	}
	    	System.out.println("");
	    	System.out.println("*******Highest marks in each subject with roll no******");
	    	for(int i=0;i<?.length;i++)
	    	{
	    		
	    	}

for(int i=0;i<;i++)
je ne sais pas comment remplir mon for < ?.length
veuillez m'aidez svp

domxaline · Answer

il n'y a personne pour m'aider svp

domxaline · Answer

void HighestMarks()
	    {
	    	for(int j=0;j<RollNo;j++)
	    	{
	    	  max=0;
	    	  for(int i=0;i<3;i++)
	    	  {
	    		if (RollNo>max)
	    		{
	    			max1=RollNo;
	    		}
	    		
	    	}
il n'ya personne pour me aider
où sont parti tous les génie informatique?

domxaline · Answer

void HighestMarks() { for(int j=0;j max1) max1 = sub1; if(sub2>max2) max2=sub2; if(sub3>max3) max3=sub3; System.out.println(max1); } System.out.println(""); en ecrivant ainsi le resultat est: ENTER YOUR CHOICE: 4 #2 10.0 10.0 10.0 *******Highest marks in each subject with roll no****** 14.0 14.0 14.0 *******Highest marks in each subject with roll no****** 14.0 14.0 14.0 *******Highest marks in each subject with roll no***** veuillez m'aidez svp

domxaline · Answer

j'ecris ainis

    void HighestMarks()
        {
         for(int j=0;j<RollNo;j++)
         {
          max=0;
          for(int i=0;i<3;i++)
          {
           if(RollNo>max)
            max1=RollNo;
          }
          System.out.println("highest marks is:"+max1);
         }
       
         System.out.println("*******Highest marks in each subject with roll 


mais le result s'affiche RollNO
Choose your choice....
1)PASS ENTRY
2)DISPLAY ALL RECORDS
3)DISPLAT TOTAL MARKS for all students
4)DISPLAT HIGHEST MARKS in each subject
5 DISPLAY student who recived highest total marks
6 Exit
ENTER YOUR CHOICE:
4
#2
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
highest marks is:10.0
*******Highest marks in each subject with roll no******
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0
highest marks is:20.0

domxaline · Answer

ok j'ai reussi faire le prg,

 void HighestMarks()
	    {
	    		max=0;
	    		for(int i=0;i<3;i++)
	    		{
	    			if(sub1>sub2)
	    				max=sub1;
	    			else
	    				max=sub2;
	    			if (sub2>sub3)
	    				max=sub2;
	    			else
	    				max=sub3;	
	    		}
	    		System.out.println("highest marks RollNo "+RollNo+" is "+max);
	    }
	    

il me reste encore à faire 
void StudHighestMarks()
pouvez vous m'aider svp

domxaline · Answer

donnez moi une idée

void StudHighestMarks()
	    {
	    	
	    	for(int i=0;i<RollNo;i++)
	    	{
	    		if(TotalMarks>max1)//à cette ligne j'hésite,donnez moi idée 	
	    		{
	    			max1=tmp;		
	    			System.out.println(tmp);
	    		}
	    	}
	    }

domxaline · Answer

il n'ya personne pour m'aider svp

domxaline · Answer

j'écris ainsi mais resultat pas bon

void StudHighestMarks()
	    {
	    	max=0;
	    	for(int j=0;j<RollNo;j++)
	    	{
	    		if (TotalMarks >max) 
	    	      {
	    	        max = TotalMarks;
	    	      }
	    		else
	    			min=(int) TotalMarks;

	    	      
	    	      System.out.println("highest marks RollNo is "+max);
	    	 }

	    	}

aidez moi svp

Java:prg suivant me donne aucun output

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