Einstellung von Doppel in C++ gibt seltsame Zahlen

Question

Ich initialisiere ein 2D-Doppel-Array in C++, einige Elemente auf 0 und andere auf 100. Nachdem ich jedoch den Wert initialisiert habe, drucke ich es aus und bekomme wirklich seltsame Zahlen (wie folgende):

6.91599e-310 
2.96439e-323 
6.95262e-310 
3.20006e-319 
6.52231e-319 
4.94066e-324 
1.63971e-319 

Wie kann ich es so machen, dass das System 0 anstelle davon ausgibt? Ich habe bereits versucht fixed << setprecision(4) << setw(10), aber ich werde immer noch Zahlen mit einer Breite viel größer als 10 und mit mehr als 4 Nachkommastellen bekommen. Ich weiß, dass Computer Probleme mit Fließkomma haben, aber warum bekomme ich einige Werte als 0 und andere als die oben genannten gedruckt? Ich bin wirklich verblüfft.

EDIT:

Hier ist meine (relevanten) Code:

void initializeArray (double Array[20][20]) { 
    for (int i = 0; i < 20; i++) { 
     for (int j = 0; j < 20; j++) { 
      if ((j == 0) || (j == 19)) { 
       Array[i][j] = 0.0; 
      } 
      else if ((i == 0) || (i == 19)) { 
       Array[i][j] = 100.0; 
      } 
     } 
    } 
} 

void printArray (double Array[20][20]) { 
    for (int i = 0; i < 20; i++) { 
     for (int j = 0; j < 19; j++) { 
      cout << setprecision(4) << fixed << setw(10) << Array[i][j] << ","; 
     } 
     cout << setprecision(4) << fixed << setw(10) << Array[i][19] << endl; 
    } 
} 

Answer 1

Der folgende Codeblock scheint fehlerhaft.

  if ((j == 0) || (j == 19)) { 
      Array[i][j] = 0.0; 
     } 
     else if ((i == 0) || (i == 19)) { 
      Array[i][j] = 100.0; 
     } 

Es ignoriert eine Menge der Elemente des Arrays. Ich wette, dass diese Elemente nicht initialisiert sind.

Hier ist ein aktuelles Programm, das zeigt, dass viele der Array-Elemente nicht initialisiert sind.

#include <iostream> 

void initializeArray (double Array[20][20]) { 
    for (int i = 0; i < 20; i++) { 
     for (int j = 0; j < 20; j++) { 
     if ((j == 0) || (j == 19)) { 
      Array[i][j] = 0.0; 
     } 
     else if ((i == 0) || (i == 19)) { 
      Array[i][j] = 100.0; 
     } 
     else 
     { 
      std::cout << "Not setting the value of Array[" << i << "][" << j << "]\n"; 
     } 
     } 
    } 
} 

int main() 
{ 
    double Array[20][20]; 
    initializeArray (Array); 
} 

Ausgang:

Not setting the value of Array[1][1] 
Not setting the value of Array[1][2] 
Not setting the value of Array[1][3] 
Not setting the value of Array[1][4] 
Not setting the value of Array[1][5] 
Not setting the value of Array[1][6] 
Not setting the value of Array[1][7] 
Not setting the value of Array[1][8] 
Not setting the value of Array[1][9] 
Not setting the value of Array[1][10] 
Not setting the value of Array[1][11] 
Not setting the value of Array[1][12] 
Not setting the value of Array[1][13] 
Not setting the value of Array[1][14] 
Not setting the value of Array[1][15] 
Not setting the value of Array[1][16] 
Not setting the value of Array[1][17] 
Not setting the value of Array[1][18] 
Not setting the value of Array[2][1] 
Not setting the value of Array[2][2] 
Not setting the value of Array[2][3] 
Not setting the value of Array[2][4] 
Not setting the value of Array[2][5] 
Not setting the value of Array[2][6] 
Not setting the value of Array[2][7] 
Not setting the value of Array[2][8] 
Not setting the value of Array[2][9] 
Not setting the value of Array[2][10] 
Not setting the value of Array[2][11] 
Not setting the value of Array[2][12] 
Not setting the value of Array[2][13] 
Not setting the value of Array[2][14] 
Not setting the value of Array[2][15] 
Not setting the value of Array[2][16] 
Not setting the value of Array[2][17] 
Not setting the value of Array[2][18] 
Not setting the value of Array[3][1] 
Not setting the value of Array[3][2] 
Not setting the value of Array[3][3] 
Not setting the value of Array[3][4] 
Not setting the value of Array[3][5] 
Not setting the value of Array[3][6] 
Not setting the value of Array[3][7] 
Not setting the value of Array[3][8] 
Not setting the value of Array[3][9] 
Not setting the value of Array[3][10] 
Not setting the value of Array[3][11] 
Not setting the value of Array[3][12] 
Not setting the value of Array[3][13] 
Not setting the value of Array[3][14] 
Not setting the value of Array[3][15] 
Not setting the value of Array[3][16] 
Not setting the value of Array[3][17] 
Not setting the value of Array[3][18] 
Not setting the value of Array[4][1] 
Not setting the value of Array[4][2] 
Not setting the value of Array[4][3] 
Not setting the value of Array[4][4] 
Not setting the value of Array[4][5] 
Not setting the value of Array[4][6] 
Not setting the value of Array[4][7] 
Not setting the value of Array[4][8] 
Not setting the value of Array[4][9] 
Not setting the value of Array[4][10] 
Not setting the value of Array[4][11] 
Not setting the value of Array[4][12] 
Not setting the value of Array[4][13] 
Not setting the value of Array[4][14] 
Not setting the value of Array[4][15] 
Not setting the value of Array[4][16] 
Not setting the value of Array[4][17] 
Not setting the value of Array[4][18] 
Not setting the value of Array[5][1] 
Not setting the value of Array[5][2] 
Not setting the value of Array[5][3] 
Not setting the value of Array[5][4] 
Not setting the value of Array[5][5] 
Not setting the value of Array[5][6] 
Not setting the value of Array[5][7] 
Not setting the value of Array[5][8] 
Not setting the value of Array[5][9] 
Not setting the value of Array[5][10] 
Not setting the value of Array[5][11] 
Not setting the value of Array[5][12] 
Not setting the value of Array[5][13] 
Not setting the value of Array[5][14] 
Not setting the value of Array[5][15] 
Not setting the value of Array[5][16] 
Not setting the value of Array[5][17] 
Not setting the value of Array[5][18] 
Not setting the value of Array[6][1] 
Not setting the value of Array[6][2] 
Not setting the value of Array[6][3] 
Not setting the value of Array[6][4] 
Not setting the value of Array[6][5] 
Not setting the value of Array[6][6] 
Not setting the value of Array[6][7] 
Not setting the value of Array[6][8] 
Not setting the value of Array[6][9] 
Not setting the value of Array[6][10] 
Not setting the value of Array[6][11] 
Not setting the value of Array[6][12] 
Not setting the value of Array[6][13] 
Not setting the value of Array[6][14] 
Not setting the value of Array[6][15] 
Not setting the value of Array[6][16] 
Not setting the value of Array[6][17] 
Not setting the value of Array[6][18] 
Not setting the value of Array[7][1] 
Not setting the value of Array[7][2] 
Not setting the value of Array[7][3] 
Not setting the value of Array[7][4] 
Not setting the value of Array[7][5] 
Not setting the value of Array[7][6] 
Not setting the value of Array[7][7] 
Not setting the value of Array[7][8] 
Not setting the value of Array[7][9] 
Not setting the value of Array[7][10] 
Not setting the value of Array[7][11] 
Not setting the value of Array[7][12] 
Not setting the value of Array[7][13] 
Not setting the value of Array[7][14] 
Not setting the value of Array[7][15] 
Not setting the value of Array[7][16] 
Not setting the value of Array[7][17] 
Not setting the value of Array[7][18] 
Not setting the value of Array[8][1] 
Not setting the value of Array[8][2] 
Not setting the value of Array[8][3] 
Not setting the value of Array[8][4] 
Not setting the value of Array[8][5] 
Not setting the value of Array[8][6] 
Not setting the value of Array[8][7] 
Not setting the value of Array[8][8] 
Not setting the value of Array[8][9] 
Not setting the value of Array[8][10] 
Not setting the value of Array[8][11] 
Not setting the value of Array[8][12] 
Not setting the value of Array[8][13] 
Not setting the value of Array[8][14] 
Not setting the value of Array[8][15] 
Not setting the value of Array[8][16] 
Not setting the value of Array[8][17] 
Not setting the value of Array[8][18] 
Not setting the value of Array[9][1] 
Not setting the value of Array[9][2] 
Not setting the value of Array[9][3] 
Not setting the value of Array[9][4] 
Not setting the value of Array[9][5] 
Not setting the value of Array[9][6] 
Not setting the value of Array[9][7] 
Not setting the value of Array[9][8] 
Not setting the value of Array[9][9] 
Not setting the value of Array[9][10] 
Not setting the value of Array[9][11] 
Not setting the value of Array[9][12] 
Not setting the value of Array[9][13] 
Not setting the value of Array[9][14] 
Not setting the value of Array[9][15] 
Not setting the value of Array[9][16] 
Not setting the value of Array[9][17] 
Not setting the value of Array[9][18] 
Not setting the value of Array[10][1] 
Not setting the value of Array[10][2] 
Not setting the value of Array[10][3] 
Not setting the value of Array[10][4] 
Not setting the value of Array[10][5] 
Not setting the value of Array[10][6] 
Not setting the value of Array[10][7] 
Not setting the value of Array[10][8] 
Not setting the value of Array[10][9] 
Not setting the value of Array[10][10] 
Not setting the value of Array[10][11] 
Not setting the value of Array[10][12] 
Not setting the value of Array[10][13] 
Not setting the value of Array[10][14] 
Not setting the value of Array[10][15] 
Not setting the value of Array[10][16] 
Not setting the value of Array[10][17] 
Not setting the value of Array[10][18] 
Not setting the value of Array[11][1] 
Not setting the value of Array[11][2] 
Not setting the value of Array[11][3] 
Not setting the value of Array[11][4] 
Not setting the value of Array[11][5] 
Not setting the value of Array[11][6] 
Not setting the value of Array[11][7] 
Not setting the value of Array[11][8] 
Not setting the value of Array[11][9] 
Not setting the value of Array[11][10] 
Not setting the value of Array[11][11] 
Not setting the value of Array[11][12] 
Not setting the value of Array[11][13] 
Not setting the value of Array[11][14] 
Not setting the value of Array[11][15] 
Not setting the value of Array[11][16] 
Not setting the value of Array[11][17] 
Not setting the value of Array[11][18] 
Not setting the value of Array[12][1] 
Not setting the value of Array[12][2] 
Not setting the value of Array[12][3] 
Not setting the value of Array[12][4] 
Not setting the value of Array[12][5] 
Not setting the value of Array[12][6] 
Not setting the value of Array[12][7] 
Not setting the value of Array[12][8] 
Not setting the value of Array[12][9] 
Not setting the value of Array[12][10] 
Not setting the value of Array[12][11] 
Not setting the value of Array[12][12] 
Not setting the value of Array[12][13] 
Not setting the value of Array[12][14] 
Not setting the value of Array[12][15] 
Not setting the value of Array[12][16] 
Not setting the value of Array[12][17] 
Not setting the value of Array[12][18] 
Not setting the value of Array[13][1] 
Not setting the value of Array[13][2] 
Not setting the value of Array[13][3] 
Not setting the value of Array[13][4] 
Not setting the value of Array[13][5] 
Not setting the value of Array[13][6] 
Not setting the value of Array[13][7] 
Not setting the value of Array[13][8] 
Not setting the value of Array[13][9] 
Not setting the value of Array[13][10] 
Not setting the value of Array[13][11] 
Not setting the value of Array[13][12] 
Not setting the value of Array[13][13] 
Not setting the value of Array[13][14] 
Not setting the value of Array[13][15] 
Not setting the value of Array[13][16] 
Not setting the value of Array[13][17] 
Not setting the value of Array[13][18] 
Not setting the value of Array[14][1] 
Not setting the value of Array[14][2] 
Not setting the value of Array[14][3] 
Not setting the value of Array[14][4] 
Not setting the value of Array[14][5] 
Not setting the value of Array[14][6] 
Not setting the value of Array[14][7] 
Not setting the value of Array[14][8] 
Not setting the value of Array[14][9] 
Not setting the value of Array[14][10] 
Not setting the value of Array[14][11] 
Not setting the value of Array[14][12] 
Not setting the value of Array[14][13] 
Not setting the value of Array[14][14] 
Not setting the value of Array[14][15] 
Not setting the value of Array[14][16] 
Not setting the value of Array[14][17] 
Not setting the value of Array[14][18] 
Not setting the value of Array[15][1] 
Not setting the value of Array[15][2] 
Not setting the value of Array[15][3] 
Not setting the value of Array[15][4] 
Not setting the value of Array[15][5] 
Not setting the value of Array[15][6] 
Not setting the value of Array[15][7] 
Not setting the value of Array[15][8] 
Not setting the value of Array[15][9] 
Not setting the value of Array[15][10] 
Not setting the value of Array[15][11] 
Not setting the value of Array[15][12] 
Not setting the value of Array[15][13] 
Not setting the value of Array[15][14] 
Not setting the value of Array[15][15] 
Not setting the value of Array[15][16] 
Not setting the value of Array[15][17] 
Not setting the value of Array[15][18] 
Not setting the value of Array[16][1] 
Not setting the value of Array[16][2] 
Not setting the value of Array[16][3] 
Not setting the value of Array[16][4] 
Not setting the value of Array[16][5] 
Not setting the value of Array[16][6] 
Not setting the value of Array[16][7] 
Not setting the value of Array[16][8] 
Not setting the value of Array[16][9] 
Not setting the value of Array[16][10] 
Not setting the value of Array[16][11] 
Not setting the value of Array[16][12] 
Not setting the value of Array[16][13] 
Not setting the value of Array[16][14] 
Not setting the value of Array[16][15] 
Not setting the value of Array[16][16] 
Not setting the value of Array[16][17] 
Not setting the value of Array[16][18] 
Not setting the value of Array[17][1] 
Not setting the value of Array[17][2] 
Not setting the value of Array[17][3] 
Not setting the value of Array[17][4] 
Not setting the value of Array[17][5] 
Not setting the value of Array[17][6] 
Not setting the value of Array[17][7] 
Not setting the value of Array[17][8] 
Not setting the value of Array[17][9] 
Not setting the value of Array[17][10] 
Not setting the value of Array[17][11] 
Not setting the value of Array[17][12] 
Not setting the value of Array[17][13] 
Not setting the value of Array[17][14] 
Not setting the value of Array[17][15] 
Not setting the value of Array[17][16] 
Not setting the value of Array[17][17] 
Not setting the value of Array[17][18] 
Not setting the value of Array[18][1] 
Not setting the value of Array[18][2] 
Not setting the value of Array[18][3] 
Not setting the value of Array[18][4] 
Not setting the value of Array[18][5] 
Not setting the value of Array[18][6] 
Not setting the value of Array[18][7] 
Not setting the value of Array[18][8] 
Not setting the value of Array[18][9] 
Not setting the value of Array[18][10] 
Not setting the value of Array[18][11] 
Not setting the value of Array[18][12] 
Not setting the value of Array[18][13] 
Not setting the value of Array[18][14] 
Not setting the value of Array[18][15] 
Not setting the value of Array[18][16] 
Not setting the value of Array[18][17] 
Not setting the value of Array[18][18] 

Ich bin nicht in der Lage ein Update seit der Initialisierung Logik vorschlagen, ist mir nicht klar.