Guys any idea how to implement the said code...

Implement the IMultiSet interface below into MultiSet class

public class IMultiSet{

// add x to this multiset (x must be 0-9)

void add(int x);

// remove x from this multiset if there are occurrences of element x (x must be 0-9)

void remove(int x);

// return another multiset containing the sum of this multiset and S

public IMultiSet sum(IMultiSet S);

// return another multiset containing the intersection of this multiset and S

public IMultiSet intersection(IMultiSet S);

// return another multiset containing the difference of this multiset and S

public IMultiSet difference(IMultiSet S);

}

Note: Override the toString

// return the string equivalent of this multiset in format {x:a, y:b, z:c }

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Post them here.

public class IMultiSet{

This looks like a class definition not an interface.

Ok sir ...
Here's my code :

public class IMultiSet{
  private int multiset[];
   	
  public IMultiSet(){ 
  	multiset = new int[10];
  }
  
  // add x to this multiset
  void add(int x){
  	 if(x < multiset.length && x >= 0)
  	 	multiset[x]++;
  }

  // remove x from this multiset if there are occurrences of x is
  void remove(int x){
  	if(x < multiset.length && x >= 0)
  	   if(multiset[x]>0) multiset[x]--;
  	  
  }
  
  
  //**The union of the two multisets is the multiset 
  //**where the occurrences of an element is maximum
  // return another multiset containing the union of this multiset and S
  public IMultiSet sum(IMultiSet S){
  	  IMultiSet tmp = new IMultiSet();
  	  for(int i=0;i<multiset.length;i++){
  	  	 if(this.multiset[i]!=0 || S.multiset[i]!=0){
  	  	 	if(this.multiset[i] >= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	  }  	  
  	 return tmp; 
  }
   
  //**The intersection of two multisets is the multiset 
  //**where the occurrences of an element is minimum 
  // return another multiset containing the intersection of this multiset and S
  public IMultiSet intersection(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	 	if(this.multiset[i] <= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	   }
  	 return tmp;
  }
  
  //**The difference of two multisets are the occurrence of element x in P minus occurrence of x in Q.
  //** If the result is negative then the occurrence of the element x in the difference is 0.
  // return another multiset containing the difference of this multiset and S
  public IMultiSet difference(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]==0)
  	  	 	  tmp.multiset[i] = this.multiset[i]; 
  	  	   else if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	   	  if(this.multiset[i] - S.multiset[i] <= 0)
  	  	   	    tmp.multiset[i] = 0;
  	  	   	  else
  	  	   	    tmp.multiset[i] = this.multiset[i] - S.multiset[i];   
  	  	   }
  	  	       
  	   }
  	 return tmp;
  	
  }

  // return the string equivalent of this multiset in format {x:a, y:b, z:c }
  public String toString(){
     String tmp = "{ ";
     for(int i=0;i<multiset.length;i++){
     	 if(this.multiset[i] != 0){
     	 	tmp+= i + ":" + this.multiset[i] + ",";
     	 }
     }
     tmp+= "\b }";   
    return tmp;  
  } 
 
  public static void main(String []args){
     IMultiSet P = new IMultiSet();
     P.add(2);P.add(2);P.add(2);P.add(2);P.add(2);
     P.add(5);P.add(5);P.add(5);
     P.add(6);P.add(6);
     P.add(8);P.add(8);
     
     IMultiSet Q = new IMultiSet();  
     Q.add(1);Q.add(1);Q.add(1);
     Q.add(2);
     Q.add(6);Q.add(6);Q.add(6);
     Q.add(7);Q.add(7); 
     Q.add(9);Q.add(9);Q.add(9);Q.add(9);Q.add(9);
     
     System.out.println("P = " + P.toString());
     System.out.println("Q = " + Q.toString());
     System.out.println("P U Q = " + P.sum(Q));
     System.out.println("P intersection Q = " + (P.intersection(Q)).toString());
     System.out.println("P - Q = " + (P.difference(Q)).toString());
        	
  }  

}

Kindly check if there's any problem ...
Thank you..

The problem is how to interchange the numbers that has been inputted..
For example, the changing of numbers of P and Q...

Kindly check if there's any problem ...

What happens when you execute it?

Please edit your code and wrap it in code tags (see [code] icon above input box)
to make it more readable.

public class IMultiSet{
  private int multiset[];
   	
  public IMultiSet(){ 
  	multiset = new int[10];
  }
  
  // add x to this multiset
  void add(int x){
  	 if(x < multiset.length && x >= 0)
  	 	multiset[x]++;
  }

  // remove x from this multiset if there are occurrences of x is
  void remove(int x){
  	if(x < multiset.length && x >= 0)
  	   if(multiset[x]>0) multiset[x]--;
  	  
  }
  
  public IMultiSet sum(IMultiSet S){
  	  IMultiSet tmp = new IMultiSet();
  	  for(int i=0;i<multiset.length;i++){
  	  	 if(this.multiset[i]!=0 || S.multiset[i]!=0){
  	  	 	if(this.multiset[i] >= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	  }  	  
  	 return tmp; 
  }
   
  public IMultiSet intersection(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	 	if(this.multiset[i] <= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	   }
  	 return tmp;
  }
  
  public IMultiSet difference(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]==0)
  	  	 	  tmp.multiset[i] = this.multiset[i]; 
  	  	   else if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	   	  if(this.multiset[i] - S.multiset[i] <= 0)
  	  	   	    tmp.multiset[i] = 0;
  	  	   	  else
  	  	   	    tmp.multiset[i] = this.multiset[i] - S.multiset[i];   
  	  	   }
  	  	       
  	   }
  	 return tmp;
  	
  }

  // return the string equivalent of this multiset in format {x:a, y:b, z:c }
  public String toString(){
     String tmp = "{ ";
     for(int i=0;i<multiset.length;i++){
     	 if(this.multiset[i] != 0){
     	 	tmp+= i + ":" + this.multiset[i] + ",";
     	 }
     }
     tmp+= "\b }";   
    return tmp;  
  } 
 
  public static void main(String []args){
     IMultiSet P = new IMultiSet();
     P.add(2);P.add(2);P.add(2);P.add(2);P.add(2);
     P.add(5);P.add(5);P.add(5);
     P.add(6);P.add(6);
     P.add(8);P.add(8);
     
     IMultiSet Q = new IMultiSet();  
     Q.add(1);Q.add(1);Q.add(1);
     Q.add(2);
     Q.add(6);Q.add(6);Q.add(6);
     Q.add(7);Q.add(7); 
     Q.add(9);Q.add(9);Q.add(9);Q.add(9);Q.add(9);
     
     System.out.println("The value of P");
     System.out.println("P = " + P.toString());
     System.out.println("The value of Q");
     System.out.println("Q = " + Q.toString());
     System.out.println("\nP U Q = " + P.sum(Q));
     System.out.println("P Intersection Q = " + (P.intersection(Q)).toString());
     System.out.println("P - Q = " + (P.difference(Q)).toString());
        	
  }  

}

What happened? Your code looks the same. Did you select the code and press the (CODE) icon?
It should look like this:

public static void main(String []args){
   IMultiSet P = new IMultiSet();
   P.add(2);P.add(2);P.add(2);P.add(2);P.add(2);
    ...
public class IMultiSet{
  private int multiset[];
   	
  public IMultiSet(){ 
  	multiset = new int[10];
  }
  
  // add x to this multiset
  void add(int x){
  	 if(x < multiset.length && x >= 0)
  	 	multiset[x]++;
  }

  // remove x from this multiset if there are occurrences of x is
  void remove(int x){
  	if(x < multiset.length && x >= 0)
  	   if(multiset[x]>0) multiset[x]--;
  	  
  }
  
  public IMultiSet sum(IMultiSet S){
  	  IMultiSet tmp = new IMultiSet();
  	  for(int i=0;i<multiset.length;i++){
  	  	 if(this.multiset[i]!=0 || S.multiset[i]!=0){
  	  	 	if(this.multiset[i] >= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	  }  	  
  	 return tmp; 
  }
   
  public IMultiSet intersection(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	 	if(this.multiset[i] <= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	   }
  	 return tmp;
  }
  
  public IMultiSet difference(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]==0)
  	  	 	  tmp.multiset[i] = this.multiset[i]; 
  	  	   else if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	   	  if(this.multiset[i] - S.multiset[i] <= 0)
  	  	   	    tmp.multiset[i] = 0;
  	  	   	  else
  	  	   	    tmp.multiset[i] = this.multiset[i] - S.multiset[i];   
  	  	   }
  	  	       
  	   }
  	 return tmp;
  	
  }

  // return the string equivalent of this multiset in format {x:a, y:b, z:c }
  public String toString(){
     String tmp = "{ ";
     for(int i=0;i<multiset.length;i++){
     	 if(this.multiset[i] != 0){
     	 	tmp+= i + ":" + this.multiset[i] + ",";
     	 }
     }
     tmp+= "\b }";   
    return tmp;  
  } 
 
  public static void main(String []args){
     IMultiSet P = new IMultiSet();
     P.add(2);P.add(2);P.add(2);P.add(2);P.add(2);
     P.add(5);P.add(5);P.add(5);
     P.add(6);P.add(6);
     P.add(8);P.add(8);
     
     IMultiSet Q = new IMultiSet();  
     Q.add(1);Q.add(1);Q.add(1);
     Q.add(2);
     Q.add(6);Q.add(6);Q.add(6);
     Q.add(7);Q.add(7); 
     Q.add(9);Q.add(9);Q.add(9);Q.add(9);Q.add(9);
     
     System.out.println("The value of P");
     System.out.println("P = " + P.toString());
     System.out.println("The value of Q");
     System.out.println("Q = " + Q.toString());
     System.out.println("\nP U Q = " + P.sum(Q));
     System.out.println("P Intersection Q = " + (P.intersection(Q)).toString());
     System.out.println("P - Q = " + (P.difference(Q)).toString());
        	
  }  

}

Nothing has changed.

public class IMultiSet{
  private int multiset[];
   	
  public IMultiSet(){ 
  	multiset = new int[10];
  }
  
  // add x to this multiset
  void add(int x){
  	 if(x < multiset.length && x >= 0)
  	 	multiset[x]++;
  }

  // remove x from this multiset if there are occurrences of x is
  void remove(int x){
  	if(x < multiset.length && x >= 0)
  	   if(multiset[x]>0) multiset[x]--;
  	  
  }
  
  public IMultiSet sum(IMultiSet S){
  	  IMultiSet tmp = new IMultiSet();
  	  for(int i=0;i<multiset.length;i++){
  	  	 if(this.multiset[i]!=0 || S.multiset[i]!=0){
  	  	 	if(this.multiset[i] >= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	  }  	  
  	 return tmp; 
  }
   
  public IMultiSet intersection(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	 	if(this.multiset[i] <= S.multiset[i])
  	  	 	  tmp.multiset[i] = this.multiset[i];
  	  	 	else
  	  	 	  tmp.multiset[i] = S.multiset[i];  
  	  	 }
  	   }
  	 return tmp;
  }
  
  public IMultiSet difference(IMultiSet S){
  	   IMultiSet tmp = new IMultiSet();
  	   for(int i=0;i<multiset.length;i++){
  	   	   if(this.multiset[i]!=0 && S.multiset[i]==0)
  	  	 	  tmp.multiset[i] = this.multiset[i]; 
  	  	   else if(this.multiset[i]!=0 && S.multiset[i]!=0){
  	  	   	  if(this.multiset[i] - S.multiset[i] <= 0)
  	  	   	    tmp.multiset[i] = 0;
  	  	   	  else
  	  	   	    tmp.multiset[i] = this.multiset[i] - S.multiset[i];   
  	  	   }
  	  	       
  	   }
  	 return tmp;
  	
  }

  // return the string equivalent of this multiset in format {x:a, y:b, z:c }
  public String toString(){
     String tmp = "{ ";
     for(int i=0;i<multiset.length;i++){
     	 if(this.multiset[i] != 0){
     	 	tmp+= i + ":" + this.multiset[i] + ",";
     	 }
     }
     tmp+= "\b }";   
    return tmp;  
  } 
 
  public static void main(String []args){
     IMultiSet P = new IMultiSet();
     P.add(2);P.add(2);P.add(2);P.add(2);P.add(2);
     P.add(5);P.add(5);P.add(5);
     P.add(6);P.add(6);
     P.add(8);P.add(8);
     
     IMultiSet Q = new IMultiSet();  
     Q.add(1);Q.add(1);Q.add(1);
     Q.add(2);
     Q.add(6);Q.add(6);Q.add(6);
     Q.add(7);Q.add(7); 
     Q.add(9);Q.add(9);Q.add(9);Q.add(9);Q.add(9);
     
     System.out.println("The value of P");
     System.out.println("P = " + P.toString());
     System.out.println("The value of Q");
     System.out.println("Q = " + Q.toString());
     System.out.println("\nP U Q = " + P.sum(Q));
     System.out.println("P Intersection Q = " + (P.intersection(Q)).toString());
     System.out.println("P - Q = " + (P.difference(Q)).toString());
        	
  }  

}

Not making much progress. Still looks the same.
What happens when you do an Edit on your last post, select the code and then press the [CODE] icon?

Can you see what you've done after you press the Save button? Does it look like this;

public static void main(String []args){
   IMultiSet P = new IMultiSet();
   P.add(2);P.add(2);P.add(2);P.add(2);P.add(2);
    ...

The problem is how to interchange the numbers that has been inputted..
For example, the changing of numbers of P and Q...

Can you execute the program and copy its output here
and add comments to it or create a copy and edit it to show what you want done.

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