Issue with a sorting program

Processing Beginners
1

Hi!
I started created a sorting algorithm, that inserts the highest value on first place (and swaps them)

code 
ArrayList<Float> values = new ArrayList<Float>();
int n = 600, min = 0, max = 600, it = 0;
void setup() {
  size(600,600);
  for(int i = 0; i < n; i++) values.add(random(min,max));
}
void draw() {
  background(0);
  stroke(255);
  for(int i = 0; i < n; i++) {
    line(i,height,i,height-values.get(i));
  }
}
void keyPressed() { for(int i = 0; i < n; i++) sortArray(); }
void sortArray() {
  int mx = it;
  for(int i = it; i < n; i++) {
    if(mx < n && values.get(i) > values.get(mx)) {
      swap(mx,i);
      mx = i;
    }
  }
  it++;
}

void swap(int a, int b) {
  float temp = values.get(a);
  values.set(a,values.get(b));
  values.set(b,temp);
}

image
image598×599 2.11 KB

what did I do wrong?

2

Can I have more details? I don’t have an idea of what to help you with.

3

you can enlarge his code with the arrow

the graphic shows that the sorting is not complete

that’s his issue

4

What happens when you press key like 6 times?

for example this works



ArrayList<Float> values = new ArrayList<Float>();
int n = 600, min = 0, max = 600, it = 0;

void setup() {
  size(600, 600);
  for (int i = 0; i < n; i++) 
    values.add(random(min, max));
}

void draw() {
  background(0);
  stroke(255);
  for (int i = 0; i < n; i++) {
    line(i, height, i, height-values.get(i));
  }
}

void keyPressed() {
  for (int i2 = 0; i2 < 7; i2++) {
    it=0; 
    for (int i = 0; i < n; i++)
      sortArray();
  }
}

void sortArray() {
  int mx = it;
  for (int i = it; i < n; i++) {
    if (mx < n && values.get(i) > values.get(mx)) {
      swap(mx, i);
      mx = i;
    }
  }
  it++;
}

void swap(int a, int b) {
  float tempA = values.get(a);
  float tempB = values.get(b);

  values.set(a, tempB);
  values.set(b, tempA);
}

maybe you have to repeat not 7 but until there is no swapping occured

5

Hey @CodeMasterX, maybe you can use the sort() method in processing.
This is an implementation:

void setup() {
int[] array  = new int[10];
for(int i = 0; i < 100; i+= 10) {
  array[i] = i+((int)random(1000);
}
 printArray(array);
 array = sort(array);
 printArray(array); 
}
6

similar:

import java.util.Collections;  // Import the Collections class

ArrayList<Float> list = new ArrayList();

// --------------------------------------------------------------------------------

list.add (17.1); 
list.add (7.7);
list.add (12.9);

// -----------------------------------------------
// Use 

println(list);  

Collections.sort(list); 

println(list);
7

The whole purpose of the program is to create a sorting algorithm : P

8

I found a problem : P

ArrayList<Float> values = new ArrayList<Float>();
int n = 600, min = 0, max = 600, it = 0;
void setup() {
  size(600,600);
  for(int i = 0; i < n; i++) values.add((float)i);//random(min,max));
}
void draw() {
  background(0);
  stroke(255);
  for(int i = 0; i < n; i++) {
    line(i,height,i,height-values.get(i));
  }
}
void keyPressed() { while( sortArray()); }
boolean sortArray() {
  int mx = it;
  boolean aaa = true;
  for(int i = 0; i < n; i++) {
    if(mx < n && i > mx && values.get(i) > values.get(mx)) {
      swap(i,mx);
      mx = i;
      aaa = false;
    }
  }
  it++;
  return !aaa;
}

void swap(int a, int b) {
  float temp = values.get(a);
  values.set(a,values.get(b));
  values.set(b,temp);
}

it returns this:

image
image599×597 1.86 KB

1 Like