How to separate my output by comma in java-CodePudding

I made this program to calculate set of numbers

public void himpunanIrisan(){
     System.out.print("The Result is  {");
     for(int k=1; k<=setofB; k  ){
         boolean Sama = false;
         for(int i=1; i<=setofA; i  ){
             if(numberB[k] == numberA[i]){
                 Sama = true;
             }
         } if (Sama==true){
             System.out.print(numberB[k]  ",");
     }
     } System.out.println("}");
 }

and the output will show like this

The Result is {1,2,}

is there any way so the other comma will dissepear?

CodePudding user response：

Change this line:

System.out.print(numberB[k]  ",");

to this should work.

System.out.print(numberB[k]  (k < setofB ? "," : ""));

CodePudding user response：

Using a joining collector would be easier and help you avoid reinventing the wheel. Additionally, converting the arrays to Sets would perform better than a nested loop over two arrays (O(m n) instead of O(m*n), where m and n are the sizes of the two array):

Set<Integer> setB = stream(numberB).boxed().collect(Collectors.toSet());

System.out.println(
        Arrays.stream(numberA)
               .boxed()
               .filter(setB::contains)
               .map(Object::toString)
               .collect(Collectors.joining(",", "{", "}"))
);

CodePudding user response：

Idea from How to delete stuff printed to console by System.out.println()?

You can use

System.out.print("\b");

To delete the "," character from STDOUT (see link for how to make it work in eclipse). Or you can change the code to something like this for example:

public void himpunanIrisan(){
 boolean isFirst = true;
 System.out.print("The Result is  {");
 for(int k=1; k<=setofB; k  ){
     boolean Sama = false;
     for(int i=1; i<=setofA; i  ){
         if(numberB[k] == numberA[i]){
             Sama = true;
         }
     } 
       if (Sama==true){
         if(isFirst) {
            System.out.print(numberB[k]);
            isFirst = false;
         } else {
            System.out.print(","   numberB[k]);
         }
         
      }
 } System.out.println("}");
}

CodePudding user response：

The StringJoiner is really convenient for such cases.

public void himpunanIrisan(){
     StringJoiner joiner = new StringJoiner(",");

     for(int k=1; k<=setofB; k  ){
         boolean sama = false;

         for(int i=1; i<=setofA; i  ){
             if(numberB[k] == numberA[i]) sama = true;
         } 

         if(sama) joiner.add(numberB[k]);
     }

     System.out.printf("The Result is {%s}", joiner.toString());
}

You won't have any extra comma at the end of the output.

CodePudding user response：

dellete last two Prints and add this* print in to seccond for loop :

System.out.println( numberB[k] (k<setofB ? "," : " }"));

CodePudding user response：

I have assumed that you are just a beginner and trying to learn that's why I try to use basic level solution.

    public void himpunanIrisan(){
        int[] numberB = {0,1,2,3,4};
        int setofB = numberB.length-1;
        int[] numberA = {0,1,2,5,6};
        int setofA = numberA.length-1;
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append("The Result is  {");
        boolean initParam = true;
        for(int k=1; k<=setofB; k  ){
            boolean Sama = false;
            for(int i=1; i<=setofA; i  ){
                if(numberB[k] == numberA[i]){
                    Sama = true;
                }
            } if (Sama && initParam){
                initParam = false;
                stringBuilder.append(numberB[k]);
            } else if(Sama) {
                stringBuilder.append(",");
                stringBuilder.append(numberB[k]);
            }
        }
        stringBuilder.append("}");
        System.out.println(stringBuilder);
    }
}

The Result is {1,2}