Syntax error on token "==", invalid Assignment Operator

TheTakuCat

Hello, I am new to processing. And I am really stuck I'm currently try to make a object move left to right or right to left randomly.

 int z = random(1);

    if (z == 1) {
      check == true;
    }

    if (z == 0) {
      check == false;
    }



  if (check == true) {

  x = 0;

    }

    if (check == false) {

      x = 500;

    }

    y = random(410, 440);

    x1 = 25;

    y1 = 50;

    if (check == true) {

  dx = SPEED2 * random(0.5, 0.8);
    }

    if (check == false) {

  dx = -dx;
    }

however the line (check == true) has a error on it. Any idea how i can fix this?

Chrisir

must be
check = false;

Chrisir

Welcome to processing! It's great!

• the double == is for comparison (as in if)

• the single = is for assignment (give the variable on the left the result of what's on the right)

you mostly have that right anyway.

Greetings, Chrisir ;-)

TheTakuCat

Hmm, then it says cannot convert float to int.. for (int z = random(1))

Chrisir

you might want to use setup() and draw()

pls read the section "hello mouse" here:

http://www.processing.org/tutorials/overview/

Chrisir

you wrote:

Hmm, then it says cannot convert float to int.. for (int z = random(1))

hm,

int z = int (random(1));

TheTakuCat

Oh, thank you i figure it out!

Chrisir

here...

int z = int (random(1)); 
boolean check = false ; 

int x;
int y;

int x1;
int y1;

float  dx=0;
float  dy;

int SPEED2 = 0;


if (z == 1) { 
  check = true;
}


if (z == 0) {
  check = false;
}

if (check == true) { 
  x = 0;
} 
if (check == false) { 
  x = 500;
} 
y = int (random(410, 440)); 
x1 = 25; 
y1 = 50;


if (check == true) {
  dx = SPEED2 * random(0.5, 0.8);
}

if (check == false) {
  dx = -dx;
}

//

Chrisir

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GoToLoop

For pure boolean comparisons like:
if (check == true) {} and if (check == false) {}

A more elegant (and possibly better performance) coding is:
if (check) {} and if (!check) {}

colouredmirrorball

int z = int (random(1));

This will always be 0 (so check will always be false). Run the following code:

for(int i = 0; i < 50; i++)
{
  println(random(1) + "  |  " + int(random(1)));
}

The reason is that int() always rounds down to an integer (it removes the part that comes after the decimal point entirely). The solution is to take a random number between 0 and 2:

int z = int (random(2));
boolean check = false ;

if (z == 1) {
  check = true;
}

You don't need the second if statement to check if z is equal to 0, because check is false by default so you're not changing anything. Also in the improbable case z would be equal to 2 one day (not sure if this is even possible), it will be taken care of.