ofstream alles auf meine Datei zweimal schreiben

Question

Also habe ich ein kurzes Programm, um eine Kostenmatrix zu einer Datei zu generieren, aber wenn ich es ausführe, wird alles in der Datei zweimal angezeigt.

Hier ist, was ich habe:

#include <cstdlib> 
    #include <fstream> 

    using namespace std; 

    int main(){ 

     int V = rand() % 15 + 5; 
     int graph[V][V]; 
     for(int i = 0; i < V; i++){ 
     for(int j = 0; j < V; j++){ 
     graph[i][j] = rand() % 50; 
     } 
     } 
    for(int i = 0; i < V; i++){ 
     graph[i][i] = 0; 
    } 

    ofstream fout; 
    fout.open("graphTest.txt", ios::app); 

    fout << V << endl; 

    for(int i = 0; i < V; i++){ 
    for(int j = 0; j < V; j++){ 
     fout << graph[i][j] << ", "; 
    } 
    fout << endl; 
    } 

fout.close(); 
return 0; 
} 

Und hier ist es, was die Datei zeigt:

18 
0, 27, 15, 43, 35, 36, 42, 49, 21, 12, 27, 40, 9, 13, 26, 40, 26, 22, 
36, 0, 18, 17, 29, 32, 30, 12, 23, 17, 35, 29, 2, 22, 8, 19, 17, 43, 
6, 11, 0, 29, 23, 21, 19, 34, 37, 48, 24, 15, 20, 13, 26, 41, 30, 6, 
23, 12, 20, 0, 31, 5, 25, 34, 27, 36, 5, 46, 29, 13, 7, 24, 45, 32, 
45, 14, 17, 34, 0, 43, 0, 37, 8, 26, 28, 38, 34, 3, 1, 4, 49, 32, 
10, 26, 18, 39, 12, 0, 36, 44, 39, 45, 20, 34, 28, 17, 1, 47, 2, 17, 
42, 2, 6, 1, 30, 36, 0, 15, 39, 44, 19, 40, 29, 31, 17, 47, 21, 31, 
25, 9, 27, 17, 6, 47, 3, 0, 15, 6, 33, 19, 24, 28, 21, 32, 29, 3, 
19, 20, 18, 8, 15, 40, 49, 46, 0, 18, 45, 46, 1, 21, 5, 29, 38, 14, 
28, 41, 0, 43, 0, 34, 14, 24, 14, 0, 6, 43, 41, 27, 15, 9, 36, 32, 
1, 37, 28, 25, 7, 24, 21, 8, 45, 29, 0, 35, 43, 18, 28, 43, 11, 28, 
29, 26, 4, 43, 13, 13, 38, 6, 40, 4, 18, 0, 38, 19, 17, 17, 46, 24, 
43, 20, 33, 40, 49, 22, 25, 44, 40, 5, 39, 4, 0, 19, 32, 42, 14, 47, 
7, 5, 4, 48, 11, 22, 28, 49, 43, 46, 18, 40, 22, 0, 10, 5, 1, 11, 
30, 28, 5, 20, 36, 44, 26, 22, 15, 8, 16, 32, 8, 24, 0, 12, 24, 0, 
36, 2, 49, 29, 0, 18, 21, 23, 31, 31, 30, 33, 44, 10, 13, 0, 31, 49, 
46, 9, 23, 13, 18, 40, 45, 26, 16, 34, 40, 40, 34, 26, 42, 36, 0, 45, 
6, 29, 18, 37, 12, 48, 22, 9, 9, 36, 10, 42, 37, 6, 1, 13, 22, 0, 
18 
0, 27, 15, 43, 35, 36, 42, 49, 21, 12, 27, 40, 9, 13, 26, 40, 26, 22, 
36, 0, 18, 17, 29, 32, 30, 12, 23, 17, 35, 29, 2, 22, 8, 19, 17, 43, 
6, 11, 0, 29, 23, 21, 19, 34, 37, 48, 24, 15, 20, 13, 26, 41, 30, 6, 
23, 12, 20, 0, 31, 5, 25, 34, 27, 36, 5, 46, 29, 13, 7, 24, 45, 32, 
45, 14, 17, 34, 0, 43, 0, 37, 8, 26, 28, 38, 34, 3, 1, 4, 49, 32, 
10, 26, 18, 39, 12, 0, 36, 44, 39, 45, 20, 34, 28, 17, 1, 47, 2, 17, 
42, 2, 6, 1, 30, 36, 0, 15, 39, 44, 19, 40, 29, 31, 17, 47, 21, 31, 
25, 9, 27, 17, 6, 47, 3, 0, 15, 6, 33, 19, 24, 28, 21, 32, 29, 3, 
19, 20, 18, 8, 15, 40, 49, 46, 0, 18, 45, 46, 1, 21, 5, 29, 38, 14, 
28, 41, 0, 43, 0, 34, 14, 24, 14, 0, 6, 43, 41, 27, 15, 9, 36, 32, 
1, 37, 28, 25, 7, 24, 21, 8, 45, 29, 0, 35, 43, 18, 28, 43, 11, 28, 
29, 26, 4, 43, 13, 13, 38, 6, 40, 4, 18, 0, 38, 19, 17, 17, 46, 24, 
43, 20, 33, 40, 49, 22, 25, 44, 40, 5, 39, 4, 0, 19, 32, 42, 14, 47, 
7, 5, 4, 48, 11, 22, 28, 49, 43, 46, 18, 40, 22, 0, 10, 5, 1, 11, 
30, 28, 5, 20, 36, 44, 26, 22, 15, 8, 16, 32, 8, 24, 0, 12, 24, 0, 
36, 2, 49, 29, 0, 18, 21, 23, 31, 31, 30, 33, 44, 10, 13, 0, 31, 49, 
46, 9, 23, 13, 18, 40, 45, 26, 16, 34, 40, 40, 34, 26, 42, 36, 0, 45, 
6, 29, 18, 37, 12, 48, 22, 9, 9, 36, 10, 42, 37, 6, 1, 13, 22, 0, 

Ich bin nicht sicher, warum es zweimal durch ist Looping

Answer 1

Sie Ihre Datei mit ios::app geöffnet flags, so dass es die Daten an eine bestehende Datei aus einem früheren Lauf anfügt:

fout.open("graphTest.txt", ios::app); 
         // ^^^^^^^^ 

Ihre Datei öffnen Sie mit den ios::trunc Flag die Daten aus früheren Läufen zu überschreiben:

fout.open("graphTest.txt", ios::trunc); 
         // ^^^^^^^^^^ 

---

Als Randbemerkung:

Der Grund, warum Sie die gleiche Reihenfolge in der Datei sehen Als das Produkt der nachfolgenden Läufe ist Ihr Programm, weil Sie versäumt haben, den Zufallsgenerator zu initialisieren. Sie müssen z.B.

seed(time(NULL)); 

einmal am Anfang von main().