Thread: Help generating random permutations from array list

There is no output for this code. I don't know why. It seems like it should work. Can someone please let me know what they think i need to change. Here is the problem.

https://students.ga.desire2learn.com...eeResponse.pdf

 
 
 
import java.util.Random; //imports the Random java class
public class PermutationGenerator
 
 
  {
  /*This method iterates the nextPermutation() method 10 times
   *to produce 10 differernt arrays of size 10 with integers
   *1 to 10 inclusive*/
 
  public void PGenerator()
  {
 
  PermutationGenerator a = new PermutationGenerator();
  for (int i=0;i<10;i++) a.nextPermutation();//This loop repeats the nextPermutation method 10 times to produce 10 different arrays
  }
 
  /*This method returns an array of 10 integers from 
   *1 to 10 inclusive in a random order by creating a 
   *new array from permutations of a base array*/
  public int[] nextPermutation()
  {
    Random rand = new Random();//Creates the random generator
    int baseSize = 0;//Initializes the base counter as 0
    int[] base = new int[10];//Initializes the base array
    for (int i = 0; i<10; i++){ //This loop fills up the base array with integers 1 to 10 inclusive
      base[i] = i + 1;
      baseSize++;//Increases the counter for base size
      System.out.println (base);
    }
    int[] mutation = new int[10];//Initializes the mutation array
    for (int i = 0; i<10; i++){
      int a = rand.nextInt(baseSize); //Picks a random index between 0 and the length of the base array
      mutation[i] = base[a]; //Sets the ith index of the result mutation array to the value at a in the base
      for (int j = a; j<baseSize - 1; j++){
        base[j] = base[j + 1];//This loop deletes the value at index a in the base array to prevent it from being chosen again
      System.out.println (base);
      }
      baseSize--;//Decreases the length of the base array
    }
    return mutation;
  }
 
 
 
public static void main(String[] args)
{
}
}
 
 
public static void main(String[] args)
{
}

i just tried that and not even the first part is being executed.

Nothing is executed. It still doesn't print anything for any step.

So take Norm's advice, and locate the first method to be called, and see what it does. Surely at least one method gets called somewhere, sometime, right? Start there.

I placed a println method at each step and nothing is printed. There is no error message.

I edited the original post to reflect changes.

they are in the code. maybe i did not put them in the right spots? there are two.