stdvector - C++: Dealing with 'Vector subscript out of range' -

using openframeworks 0.7.4, vs2012, v100 platform toolset.

i'm making family of circles, each spawning children circles if circles.size() < 200 && rand() % 20 == 0.

each circle pushed std::vector using push_back() function.

the lines of polygon constructed children circles drawn according std::vector<std::vector<int>> each of elements contain 6 integer values, each being previous child , current child circle's x , y positions, , index of previous , current child circle in mentioned std::vector.

and @ random times error.

i tried using cout check how many elements 2 vectors hold , results not constant:

1: circles.size() = 57, lines.size() = 56; 2: circles.size() = 42, lines.size() = 41; 3: circles.size() = 72, lines.size() = 71; 4: circles.size() = 78, lines.size() = 77; 

the error mentioned pressing 'retry' debug.

the problem must in circles.

these top parts , bottom parts when circles collapsed.

i read questions asked on stack overflow don't think problem on using = instead of push_back() or 'stack corruption'.

the source codes:

testapp.cpp

#include "testapp.h"  void testapp::setup(){ ofsetwindowshape(1200, 800); ofbackground(0, 0, 0);  lcircles = llines = 0;  circle rc = circle(600, 400); circles.push_back(rc);  ofenablealphablending(); }  void testapp::update(){ cout << circles.size() << ", " << lines.size() << endl;  if (circles.size() < 200) {     if (rand() % 20 == 0) {         int ci = rand() % circles.size();          detectindex(ci, true);          if (!circles[ci].isnear) {             circles[ci].isnear = true;              int iterant = rand() % 7 + 3;             int actual = 0;              (int cci = 0; cci < iterant; cci++) {                 circle nc = circle(circles[ci].x + cos(360 / iterant * cci * pi / 180) * spawnradius, circles[ci].y + sin(360 / iterant * cci * pi / 180) * spawnradius);                 if (!detectcircle(nc, true)) {                     circles.push_back(nc);                     actual++;                     circles[ci].radius++;                 }             }              (int sli = circles.size() - actual + 1; sli < circles.size(); sli++) {                 std::vector<int> nline;                 nline.push_back(circles[sli - 1].x);                 nline.push_back(circles[sli - 1].y);                 nline.push_back(circles[sli].x);                 nline.push_back(circles[sli].y);                 nline.push_back(sli - 1);                 nline.push_back(sli);                 lines.push_back(nline);             }              std::vector<int> nline;             nline.push_back(circles[circles.size() - actual].x);             nline.push_back(circles[circles.size() - actual].y);             nline.push_back(circles[circles.size() - 1].x);             nline.push_back(circles[circles.size() - 1].y);             nline.push_back(circles.size() - actual);             nline.push_back(circles.size() - 1);             lines.push_back(nline);         }     } } }  bool testapp::detectindex(int ci, bool change = false) { bool res = false;  (int chi = 0; chi < circles.size(); chi++) {     if (ci != chi) {         if (ofdist(circles[ci].x, circles[ci].y, circles[chi].x, circles[chi].y) < circles[ci].aradar * circles[ci].radius) {             res = true;             if (change) circles[ci].isnear = circles[chi].isnear = true;         }     } }  return res; }  bool testapp::detectcircle(circle ci, bool change = false) { bool res = false;  (int chi = 0; chi < circles.size(); chi++) {     if (ofdist(ci.x, ci.y, circles[chi].x, circles[chi].y) < ci.aradar * ci.radius) {         res = true;         if (change) ci.isnear = circles[chi].isnear = true;     } }  return res; }  void testapp::draw(){ (int dci = 0; dci < circles.size(); dci++) {     ofsetcolor(circles[dci].color);     ofcircle(circles[dci].x, circles[dci].y, circles[dci].radius);     ofnofill();     ofsetcolor(circles[dci].color, 128);     ofcircle(circles[dci].x, circles[dci].y, circles[dci].aradar * circles[dci].radius);     offill(); }  (int dli = 0; dli < lines.size(); dli++) {     ofsetcolor(circles[lines[dli][4]].color);     ofline(lines[dli][0], lines[dli][1], (lines[dli][2] + lines[dli][0]) / 2, (lines[dli][3] + lines[dli][1]) / 2);     ofsetcolor(circles[lines[dli][5]].color);     ofline(lines[dli][2], lines[dli][3], (lines[dli][2] + lines[dli][0]) / 2, (lines[dli][3] + lines[dli][1]) / 2); } }  void testapp::keypressed(int key){     ofsaveframe(); } 

non-default part of testapp.h

#define spawnradius 50  #include "circle.h"  class testapp : public ofbaseapp {     public:         ...         std::vector<circle> circles;         std::vector<std::vector<int>> lines;          bool detectindex(int ci, bool change);         bool detectcircle(circle ci, bool change);          int lcircles;         int llines; 

circle.h

#include "ofmain.h"  class circle {  public:     int x;     int y;     int radius;     int aradar;      ofcolor color;      bool isnear;      circle(int cx, int cy) {         x = cx;         y = cy;         radius = 5;         aradar = 6;          color = ofcolor(ofrandom(255));          isnear = false;     }  }; 

i don't know how use debugger in vs , code or debugger.