the three for loop blues

Programming Questions

pjacobso

in Programming Questions • 1 year ago

I've come across this issue a number of times and since I don't have a super systematic approach to dealing with it...

So say you have two nested for loops:

void setup() {
size(640,480);
background(255);
}
void draw() {
for (int i=0; i<64; i++) {
for (int j=0; j<48; j++) {
pushMatrix();
stroke(255,0,128,200);
rect(i*10, j*10, 10, 10);
popMatrix();
}}
}

what's the best way to cope with a third for loop? what would you do? below, of course, slows everything to a crawl:

void setup() {
size(640,480);
background(255);
}
void draw() {
for (int i=0; i<64; i++) {
for (int j=0; j<48; j++) {
for (int t=0; t<48; t++) {
pushMatrix();
stroke(255,0,128,200);
rect(i*10, j*10, 1+t, 10);
popMatrix();
t++;
if (t > 10){
t = 0;
}
}}}
}

define t outside the existing for loops.. Would appreciate any insight.

Replies(4)

v.k.

Re: the three for loop blues

1 year ago

Maybe this would do, at least for this need.

void setup() {
size(640,480);
background(255);
}
void draw() {
for (int i=0; i<64; i++) {
for (int j=0; j<48; j++) {
pushMatrix();
stroke(255,0,128,200);
rect(i*10, j*10, 1+(j%10), 10); // using j modulo 10 instead of a new counter
popMatrix();
//t++; // why increment t again inside loop?
/* no need, %10 do it
if (t > 10){ // also you will never reach t = 48 to leave the loop...
t = 0;
}
*/
}}
}

pjacobso

Re: the three for loop blues

1 year ago

I like your solution. Thanks. The incrementing was me thinking about getting some movement going. One could set up a seperate function if j and t really were different?

v.k.

in your code t was declared in the for loop. for(int t.... and was being reset to zero inside the loop every time it hits 10, so the condition "while" t < 48 would never met. An infinite loop... This is why the code was not working. You can have:

:) edit

void setup() {
size(640, 480,P3D);
background(255);
}
void draw() {
for (int i=0; i<64; i++) {
for (int j=0; j<48; j++) {
for (int t = 0; t < 100; t+=4)
{
pushMatrix();
translate(i*10, j*10, t*10);
stroke(255, 0, 128, 200);
box(j%10);
popMatrix();
}
}
}

pjacobso

Re: the three for loop blues

1 year ago

Thanks, this is making sense. I like it!

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