Need help for not initializing a Variable Error

Programming Questions

kivifreak

Need help for not initializing a Variable Error

in Programming Questions • 1 year ago

Can somebody help me with this error:

It sais that my local variable dirX has not been initialized (probably also dirY)

My idea is that the single life obj (pixels) should come together.

Of course im making the code more complex later.

Sry for using arrays, but i really like this old school style ^^

So on its fun at coding it and i dont want to give up by this error. Thx for helping (and or reading =D)

int xA=20;
int yA=20;
int[][] x;
int[][] y;
life lif[][];
void setup()
{x=new int[xA][yA];
y=new int[xA][yA];
lif=new life[xA][yA];
size(500,500);
smooth();
ellipseMode(CENTER);
for(int i=0;i<xA;i++)
{
for(int j=0;j<yA;j++){
lif[i][j]=new life((i*5)+int(random(5,10)),(j*5)+int(random(5,10)),i,j);
}}
}
void draw()
{background(0);
for(int i=0;i<xA;i++)
{
for(int j=0;j<yA;j++){
lif[i][j].display();
}}
}
class life{
int sX;
int sY;
life(int curx, int cury, int cursX, int cursY)
{
sX=cursX;
sY=cursY;
x[sX][sY]=curx;
y[sX][sY]=cury;
}
void display(){
int dirX;
int dirY;
int Small=1000000;
ellipse(x[sX][sY],y[sX][sY],2,2);
for(int i=0;i<xA;i++)
{
for(int j=0;j<yA;j++){
if(x[sX][sY]<x[i][j])
{if(y[sX][sY]<y[i][j])
{if((x[i][j]-x[sX][sY])+(y[i][j]-y[sX][sY])<Small){Small=(x[i][j]-x[sX][sY])+(y[i][j]-y[sX][sY]);
dirX=i;
dirY=j;}}
if(y[sX][sY]>y[i][j])
{if((x[i][j]-x[sX][sY])+(y[sX][sY]-y[i][j])<Small){Small=(x[i][j]-x[sX][sY])+(y[sX][sY]-y[i][j]);
dirX=i;
dirY=j;}}
if(y[sX][sY]==y[i][j])
{if((x[i][j]-x[sX][sY])<Small){Small=(x[i][j]-x[sX][sY]);
dirX=i;
dirY=j;}}
}
else if(x[sX][sY]==x[i][j])
{if(y[sX][sY]<y[i][j])
{if((y[i][j]-y[sX][sY])<Small){Small=(y[i][j]-y[sX][sY]);
dirX=i;
dirY=j;}}
if(y[sX][sY]>y[i][j])
{if((y[sX][sY]-y[i][j])<Small){Small=(y[sX][sY]-y[i][j]);
dirX=i;
dirY=j;}
}
if(y[sX][sY]==y[i][j])
{if((x[i][j]-x[sX][sY])<Small){Small=(x[i][j]-x[sX][sY]);
dirX=i;
dirY=j;}}
}
else{
if(y[sX][sY]<y[i][j])
{if((x[sX][sY]-x[i][j])+(y[i][j]-y[sX][sY])<Small){Small=(x[sX][sY]-x[i][j])+(y[i][j]-y[sX][sY]);
dirX=i;
dirY=j;}}
if(y[sX][sY]>y[i][j])
{if((x[sX][sY]-x[i][j])+(y[sX][sY]-y[i][j])<Small){Small=(x[sX][sY]-x[i][j])+(y[sX][sY]-y[i][j]);
dirX=i;
dirY=j;}}
if(y[sX][sY]==y[i][j])
{if((x[sX][sY]-x[i][j])<Small){Small=(x[sX][sY]-x[i][j]);
dirX=i;
dirY=j;}}
}
}}
if(dirX<x[sX][sY])
{x[sX][sY]--;}
else{x[sX][sY]++;}
if(dirY<y[sX][sY])
{y[sX][sY]--;}
else{y[sX][sY]++;}
}
}

Replies(9)

PhiLho

Re: Need help for not initializing a Variable Error

1 year ago

Ctrl+T can make your code much more readable...

The error you report indicates you declared a local variable but hasn't assigned any value to it. Unlike global variables (or class variables, which have a default value), local variables should be initialized when declared:
void display() {
int dirX = 0;
int dirY = 0;
// [...]

Chrisir

Re: Need help for not initializing a Variable Error

1 year ago

where you have

int dirX;
int dirY;

have

int dirX=0;
int dirY=0;

kivifreak

Thx, but that doesnt solve my problem =(

1 year ago

Thanks for answering so fast, but this doesnt solve my problem.

The code i programmed in the for loop should declare dirX and dirY.

So the little pixels dont fly onto the top left corner, but to their next neighbour pixel.

I really appreciate help and thx again =)

BTW this is the code with ctrl + t

int xA=20;
int yA=20;
int[][] x;
int[][] y;
life lif[][];
void setup()
{
x=new int[xA][yA];
y=new int[xA][yA];
lif=new life[xA][yA];
size(500, 500);
smooth();
ellipseMode(CENTER);
for (int i=0;i<xA;i++)
{
for (int j=0;j<yA;j++) {
lif[i][j]=new life((i*5)+int(random(5, 10)), (j*5)+int(random(5, 10)), i, j);
}
}
}
void draw()
{
background(0);
for (int i=0;i<xA;i++)
{
for (int j=0;j<yA;j++) {
lif[i][j].display();
}
}
}
class life {
int sX;
int sY;
life(int curx, int cury, int cursX, int cursY)
{
sX=cursX;
sY=cursY;
x[sX][sY]=curx;
y[sX][sY]=cury;
}
void display() {
int dirX=0;
int dirY=0;
int Small=1000000;
ellipse(x[sX][sY], y[sX][sY], 2, 2);
for (int i=0;i<xA;i++)
{
for (int j=0;j<yA;j++) {
if (x[sX][sY]<x[i][j])
{
if (y[sX][sY]<y[i][j])
{
if ((x[i][j]-x[sX][sY])+(y[i][j]-y[sX][sY])<Small) {
Small=(x[i][j]-x[sX][sY])+(y[i][j]-y[sX][sY]);
dirX=i;
dirY=j;
}
}
if (y[sX][sY]>y[i][j])
{
if ((x[i][j]-x[sX][sY])+(y[sX][sY]-y[i][j])<Small) {
Small=(x[i][j]-x[sX][sY])+(y[sX][sY]-y[i][j]);
dirX=i;
dirY=j;
}
}
if (y[sX][sY]==y[i][j])
{
if ((x[i][j]-x[sX][sY])<Small) {
Small=(x[i][j]-x[sX][sY]);
dirX=i;
dirY=j;
}
}
}
else if (x[sX][sY]==x[i][j])
{
if (y[sX][sY]<y[i][j])
{
if ((y[i][j]-y[sX][sY])<Small) {
Small=(y[i][j]-y[sX][sY]);
dirX=i;
dirY=j;
}
}
if (y[sX][sY]>y[i][j])
{
if ((y[sX][sY]-y[i][j])<Small) {
Small=(y[sX][sY]-y[i][j]);
dirX=i;
dirY=j;
}
}
if (y[sX][sY]==y[i][j])
{
if ((x[i][j]-x[sX][sY])<Small) {
Small=(x[i][j]-x[sX][sY]);
dirX=i;
dirY=j;
}
}
}
else {
if (y[sX][sY]<y[i][j])
{
if ((x[sX][sY]-x[i][j])+(y[i][j]-y[sX][sY])<Small) {
Small=(x[sX][sY]-x[i][j])+(y[i][j]-y[sX][sY]);
dirX=i;
dirY=j;
}
}
if (y[sX][sY]>y[i][j])
{
if ((x[sX][sY]-x[i][j])+(y[sX][sY]-y[i][j])<Small) {
Small=(x[sX][sY]-x[i][j])+(y[sX][sY]-y[i][j]);
dirX=i;
dirY=j;
}
}
if (y[sX][sY]==y[i][j])
{
if ((x[sX][sY]-x[i][j])<Small) {
Small=(x[sX][sY]-x[i][j]);
dirX=i;
dirY=j;
}
}
}
}
}
if (dirX<x[sX][sY])
{
x[sX][sY]--;
}
else {
x[sX][sY]++;
}
if (dirY<y[sX][sY])
{
y[sX][sY]--;
}
else {
y[sX][sY]++;
}
}
}

PhiLho

Re: Need help for not initializing a Variable Error

1 year ago

Well, it solved your problem, the one you asked help for. You just have another problem. Which I don't really understand... (neither your code...)

kivifreak

Re: Need help for not initializing a Variable Error

1 year ago

The little small pixels should actually dont go to the same spot.

I didnt declare dirX and dirY on purpose because i wanted to declare it in the for loop.

The for loop should search for the pixel closest to it and then go into its direction.

My problem is, the for loop doesnt declare the dirX or dirY, but it should declare it.

Thats what im asking for help.

So short:

Think of it as a cellular automata (as conways game of life i once did).

The little pixels try to go to their next neighbour.

Sry for my bad english im only 14 and from switzerland.

Chrisir

Re: Need help for not initializing a Variable Error

1 year ago

do you know dist()
http://www.processing.org/reference/dist_.html

gives you the dist between 2 points

good for you because you can use it often

I have to say I don't understand your Code

dirX and dirY are not changed after they are set to 0;

that means none of your ifs gives true, so dirX and dirY are not changed

what is x[][] and why do you change it in the class Life?

The for loop should search for the pixel closest to it and then go into its direction.

make sure he doesn't get compared to itself.

there are lot of examples for birds in the topics

e.g.
http://www.processing.org/learning/topics/flocking.html

kivifreak

Thx

1 year ago

Thx this complicated stuff with the arrays should only get the distance between the objects :)

Now my problem might be easier to understand.

I dont get why the if statement never gives true..

what is x[][] and why do you change it in the class Life?

Well the x[][] and y[][] are arrays that hold the x or y coordinate of the single life.

The sX and the sY are their x and y ticket.

so x[sX][sY] is the x coordination of the current live.

xA and yA are the maximum of pixels in coordinations.

This flocking code seems to be very promising but i cant find my bug.

Its exactly what im searching for. You would help me alot by finding this bug.

The goal is the pixels are going to their closest neighbour.

The reason im not using arraylist is because i want to programm much more into this pixels (i wnat them later to join to obsticles and form social 2d life organism :)

And thx again it helped a lot :)

int xA=20;
int yA=20;
int[][] x;
int[][] y;
life lif[][];
void setup()
{
x=new int[xA][yA];
y=new int[xA][yA];
lif=new life[xA][yA];
size(500, 500);
smooth();
ellipseMode(CENTER);
for (int i=0;i<xA;i++)
{
for (int j=0;j<yA;j++) {
lif[i][j]=new life((i*5)+int(random(5, 10)), (j*5)+int(random(5, 10)), i, j);
}
}
}
void draw()
{
background(0);
for (int i=0;i<xA;i++)
{
for (int j=0;j<yA;j++) {
lif[i][j].display();
}
}
}
class life {
int sX;
int sY;
life(int curx, int cury, int cursX, int cursY)
{
sX=cursX;
sY=cursY;
x[sX][sY]=curx;
y[sX][sY]=cury;
}
void display() {
int dirX=0;
int dirY=0;
float Small=1000000000;
for (int i=0;i<xA;i++)
{
for (int j=0;j<yA;j++)
{
if (dist(x[sX][sY], y[sX][sY], x[i][j], y[i][j])<Small)
{
Small=dist(x[sX][sY], y[sX][sY], x[i][j], y[i][j]);
dirX=x[i][j];
dirY=y[i][j];
}
}
}
if (dirX<x[sX][sY])
{
x[sX][sY]--;
}
else {
x[sX][sY]++;
}
if (dirY<y[sX][sY])
{
y[sX][sY]--;
}
else {
y[sX][sY]++;
}
ellipse(x[sX][sY], y[sX][sY], 2, 2);
}
}

Chrisir

Re: Need help for not initializing a Variable Error

1 year ago

maybe like this:

int xA=20;
Life lif[];
//
void setup()
{
size(800, 800);
frameRate(3);
smooth();
lif=new Life[xA*xA];
ellipseMode(CENTER);
int i2=0;
for (int i=0;i<xA;i++)
{
for (int j=0;j<xA;j++)
{
lif[i2]=new Life(
i*6+10, j*17+120,
int(random(5, 9)), int(random(5, 9)));
i2++;
}
}
}
//
void draw()
{
background(0);
for (int i=0;i<xA*xA;i++)
{
lif[i].display( i );
}
}
//
// ==============================================================
class Life {
int sX; // Pos
int sY;
float cursX; // Dir
float cursY;
Life(int curx, int cury, int _cursX, int _cursY)
{
sX=curx;
sY=cury;
cursX=_cursX*.9;
cursY=_cursY*.9;
}
//
void display(int myIndex) {
int dirX=0;
int dirY=0;
float Small=1000000;
sX+=cursX;
sY+=cursY;
sX+= random (-3, 3);
sY+= random (-3, 3);
fill(255);
ellipse(sX, sY, 2, 2);
for (int i=0;i<xA;i++) {
if (i!=myIndex) {
// http://www.processing.org/reference/dist_.html
if (dist(sX, sY, lif[i].sX, lif[i].sY )<Small) {
Small=dist(sX, sY, lif[i].sX, lif[i].sY );
if (Small>29) {
dirX=lif[i].sX-sX;
dirY=lif[i].sY-sY;
println("yes");
}
else
{
dirX=0;
dirY=0;
}
} // if
} // if
} // for
/// ---------------------------------------
println (dirX + " " + dirY);
// ---------------------------------------
//
sX+=dirX*.1;
sY+=dirY*.1;
//
}
}

Chrisir

Re: Need help for not initializing a Variable Error

1 year ago

or like this....

int xA=10;
Life lif[];
//
void setup()
{
size(800, 800);
frameRate(12);
smooth();
lif=new Life[xA*xA];
ellipseMode(CENTER);
int i2=0;
for (int i=0;i<xA;i++)
{
for (int j=0;j<xA;j++)
{
lif[i2]=new Life(
i*6+10, j*17+120,
int(random(5, 9)), int(random(5, 9)),
color (random(256), random(256), random(256)));
i2++;
}
}
}
//
void draw()
{
background(0);
for (int i=0;i<xA*xA;i++)
{
lif[i].display( i );
}
}
//
// ==============================================================
class Life {
int sX; // Pos
int sY;
float cursX; // Dir
float cursY;
color col;
Life(int curx, int cury, int _cursX, int _cursY, color _col)
{
sX=curx;
sY=cury;
cursX=_cursX*.9;
cursY=_cursY*.9;
col=_col;
}
//
void display(int myIndex) {
int dirX=0;
int dirY=0;
float Small=1000000;
//
if (sX>width-100)
{
//sX+= random (-12, -2);
// cursX=-abs(cursX);
cursX--;
}
else {
//sX+= random (-3, 3);
}
if (sY>height-100)
{
//sY+= random (-12, -2);
//cursY=-abs(cursY);
cursY--;
}
else {
//sY+= random (-3, 3);
}
// -----------------
if (sX<100)
{
//sX+= random (-12, -2);
// cursX=-abs(cursX);
cursX++;
}
else {
//sX+= random (-3, 3);
}
if (sY<100)
{
//sY+= random (-12, -2);
//cursY=-abs(cursY);
cursY++;
}
else {
//sY+= random (-3, 3);
}
cursX+=random (-1, 1);
cursY+=random (-1, 1);
sX+=cursX*.1;
sY+=cursY*.1;
fill(col);
stroke(col);
// ellipse(sX, sY, 2, 2);
point(sX, sY);
for (int i=0;i<xA;i++) {
if (i!=myIndex) {
// http://www.processing.org/reference/dist_.html
if (dist(sX, sY, lif[i].sX, lif[i].sY )<Small) {
Small=dist(sX, sY, lif[i].sX, lif[i].sY );
if (Small>29) {
dirX=lif[i].sX-sX;
dirY=lif[i].sY-sY;
println("yes");
}
else
{
dirX=0;
dirY=0;
}
} // if
} // if
} // for
//
// ---------------------------------------
println (dirX + " " + dirY);
// ---------------------------------------
//
sX+=dirX*.1;
sY+=dirY*.1;
//
}
}

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