Access violation writing location c++ for 1st dimensional difference method -


i have problem deal 1st dimensional advection equation becauseof error. got 'access viloation writing location' in console screen. sounds error memory allocation know have enough memory space allocate valuables. don`t know how deal this. give me hand please?

#include <iostream> #include <fstream> #include <cmath> using namespace std;  class differencemethod { private:     unsigned short const velocity;     unsigned short const tmax;     float const dt;     unsigned short const xmax;     unsigned short const dx;  public:     differencemethod(unsigned short tmpvelocity, unsigned short tmptmax, float tmpdt, unsigned short tmpdx, unsigned short tmpxmax)     : velocity(tmpvelocity), tmax(tmptmax), dt(tmpdt), dx(tmpdx), xmax(tmpxmax) {         float* x = new float[xmax + 1];         unsigned short* xn = new unsigned short;         (unsigned short xn = 1; xn <= xmax; xn++) {             x[xn] = 0.5*dx + (xn - 1)*dx;         }         double* f = new double[xmax + 1];         (unsigned short xn = 1; xn <= xmax; xn++) {             f[xn] = exp(-(((x[xn] - 50)*(x[xn] - 50)) / (15 * 15)));;         }         delete[] x;         x = null;         cout << "initalization completed!\n";         ofstream out;         out.open("1strun.txt");         out.precision(10);         double* fnew = new double[xmax + 1];         (unsigned short t = 1; t <= tmax / dt; t++) {             f[1] = 0;             fnew[1] = 0;             (unsigned short xn = 2; xn <= xn; xn++) {                 fnew[xn] = f[xn] - ((velocity * dt) / dx)*(f[xn] - f[xn - 1]);                 f[xn] = fnew[xn];                 if (t == 100 || t == 300|| t == 500|| t == 700) {                     if (xn == 2) {                         out << "======" << t << "=====\n";                         out << "1" << '\t' << "0\n";                     }                     out << xn << '\t' << fnew[xn] << endl;                 }             }             cout << t << " / " << (tmax / dt) << " completed\n";         }         out.close();         delete[] f;         f = null;         delete[] fnew;         fnew = null;     } };  void main(){     differencemethod *firstq = new differencemethod(1, 700, 0.1, 1, 1000); }


Comments

Post a Comment

Popular posts from this blog

sql server - Cannot query correctly (MSSQL - PHP - JSON) -

i have little problem on project. , turns out query result returns nothing when value of first name or last name has 'ñ' in it. here's code config.php: <?php ini_set('mssql.charset', 'utf-8'); header('content-type: text/html; charset=utf-8'); $servername = "192.168.1.21"; /* ip add of db server */ $connection = array("database" => "db", "uid" => "?", "pwd" => "***"); $conn = sqlsrv_connect($servername, $connection); if(!$conn){ echo "connection not established."; die(print_r(sqlsrv_errors(), true)); } ?> myquery: $idnumber = $_post["idnum"]; $response = array(); $query2 = "select clname, cfname, cmname, cqualifier student cidno = '$idnumber'"; try{ $stmt2 = sqlsrv_query($conn, $query2); } catch(pdoexeption $ex){ $response["success"] = 0; $response["message"] = "d...
Read more

php - trouble displaying mysqli database results in correct order -

i have table in database stores events , date expire. want display events on website display current events first expired events after? i have tried following sql $sql = "select noticeid, notice, noticedesc, noticeimg, noticedate, expirydate tbl_notices group noticeid ,expired order expirydate asc"; but returns expired results first due expirydate being ordered asc in query. my tbl_notice structure looks this noticeid => int(4) notice => varchar(100) noticedesc => text noticedate => timestamp noticeimg => varchar(40) expirydate => datetime expired => int(1) 0 current or 1 expired my php code is $sql = "select noticeid, notice, noticedesc, noticeimg, noticedate, expirydate tbl_notices group noticeid ,expired order expirydate asc"; $result = mysqli_query($conn,$sql); if ($result->num_rows > 0) { // output data of each row while($row = $result->fetch_assoc()) { ...
Read more

C++ Linked List -

i trying create linked list download txt file , use linked list handle file line line. when handling downloaded linked list operations performed on such text editor would. encountering problems however. seems "node(string value)" section of code has wrong though original node() declaration no arguments passes. unable figure out quite is. node.h class node { public: node(); node(string value); void setnext(node *nextnode); // allows user set "next" pointer of node points friend class linkedlist; private: string data; // data box node* next; // pointer box }; node.cpp # include <string> # include "node.h" using namespace std; node::node() { data = ""; next = null; } node::node(string value) { data = value; next = null; } void node::setnext(node *nextnode) // allows user set "next" pointer of node points { this->next = nextnode; } your #include <string> ...
Read more