ofstream私のファイルにすべて2回書き込む

Question

私はファイルへのコストマトリックスを生成する短いプログラムを持っていますが、私がそれを実行するとすべてがファイルに2回表示されます。

#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; 
} 

そして、ここでファイルを表示するものです：ここで

は、私が持っているものだ

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, 

私はそれはあなたがios::appであなたのファイルを開いた二回

Answer 1

をループしている理由はわかりません既存のファイルにデータを追加します。

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

以前の実行からのデータを上書きするios::truncフラグを使用してファイルを開きます：サイドノートとして

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

---

を：

ファイルに同一の配列を見ている理由をあなたがランダムジェネレータを初期化するのを忘れてしまったために、その後の実行の結果としてあなたのプログラムがあるからです。あなたは例えば電話をしなければなりません。

seed(time(NULL)); 

main()の冒頭に一度。