Copy Array to text file c++ error munmap_chunk() -

hi trying create text file stores value of array. program runs when try insert code copy text file error

munmap_chunk(): invalid pointer munmap_chunk(): invalid pointer

the text file created empty

#include <iostream> #include <string> #include <cstdlib> #include <fstream>  using namespace std;  int generator(void){ int state; state = 1 + rand() % 2; return state;  }   int main() {  int nwalks,nsteps,x,state;  double xsum1,xsum2,xaccum;   int *arxaccum = new int[nwalks];  int *arxsquared = new int[nwalks];  cout << "give number of walks :  ";  cin >> nwalks; cout << "give number of steps :  "; cin >> nsteps; ofstream arraydata("/home/path/xaverage.txt",ios::app);    srand(1256);  xaccum = 0.0;  xsum1 = 0.0; xsum2 = 0.0;  (int walks = 1; walks <= nwalks; walks++)  { x = 0;   (int steps = 1; steps <= nsteps; steps++)  { state = generator() ;     if (state == 1)         x += +1;     else          x += -1;  }      xaccum =+ x;      arxaccum[walks] = xaccum;      arxsquared[walks] = xaccum*xaccum;      xsum1 += arxaccum[walks];      xsum2 += arxsquared[walks];    }             (int = 1; <= nwalks; i++){           arraydata << arxaccum[i] << endl;          }     cout << " average displacement <x> : " << xsum1/nwalks << endl;   cout << " average of squared displacement <x^2> : " <<      xsum2/nwalks << endl;      return 0; }