Calculating 3D cartesian coordinates inside a cone - c++

Question

So what I am essentially trying to do here is arranging the 3D cartesian coordinates of points inside an inverted cone (radius decreases with height). The basic approach I have taken here is to have an integrally reducing height, h, and plotting points (x,y) that fall within a circle formed at height h. Since the radius of this circle is variable, I am using a simple similarity condition to determine that at every iteration. The initial height I have taken is 1000, the radius ought to initially be 3500. Also, these circles as centred at (0,0) [the z-axis passes through the vertex of the cone, and is perpendicular to the base]. Code isn't running properly, showing me an exit status of -1. Can anyone help me figure out if my implementation is off due to some size errors or something?
#include<bits/stdc++.h>
#define ll long long int
using namespace std;
int main(){
float top[1010][9000][3];
ll i = 0;
for(ll h = 999; h >=0; h--){
float r=(h+1)*(3.5);
for (ll x = floor(r) * (-1); x <= floor(r); x++){
for (ll y = floor(r) *(-1); y <= floor(r); y++){
if(pow(x,2) + pow(y,2) <= pow(floor(r),2)){
top[h][i][0] = x;
top[h][i][1] = y;
top[h][i][2] = 9.8;
i++;
}
}
}
i=0;
}
cout << "done";
for (ll m = 0; m < 1000; m++){
for(ll n = 0; n < 7000; n++){
if(top[m][n][2] == 9.8){
cout << top[m][n][0] << top[m][n][1];
}
}
}
}

Answer 1

You don't need to declare ll as long long int. The indexes you are using will fit inside of int.
Here's your problem: Change the code to this to see what's going on:
for(ll h = 999; h >=0; h--){
float r=(h+1)*(3.5);
for (ll x = floor(r) * (-1); x <= floor(r); x++){
for (ll y = floor(r) *(-1); y <= floor(r); y++){
if(pow(x,2) + pow(y,2) <= pow(floor(r),2)){
/* top[h][i][0] = x;
top[h][i][1] = y;
top[h][i][2] = 9.8; //*/
i++; // this gets really big
}
}
}
cout << "max i: " << i << endl;
i=0;
}
i gets really big and is indexing into a dimension that is only 9000.
Criticism of the code...
It looks like you are scanning the entire x,y,z block and 'testing' if the point is inside. If yes, saving the x,y coordinate of the point along with 9.8 (some field value?).
Perhaps you could forgo the float buffer and just print the {x,y} coordinates directly to see how your code works before attempting to save the output. redirect the output to a file and inspect.
cout << "{" << x << "," << y <<"}," << (i % 5 == 0 ? "\n" : " ");
Also, read up on why comparing floats with == doesn't work.