C++ ofstream 无法写入文件

Question

嘿，我正在尝试将一些数字写入文件，但是当我打开文件时它是空的。你能帮我一下吗？谢谢。

/** main function **/
int main(){

    /** variables **/
    RandGen* random_generator = new RandGen;
    int random_numbers; 
    string file_name;   

    /** ask user for quantity of random number to produce **/
    cout << "How many random number would you like to create?" << endl;
    cin >> random_numbers;

    /** ask user for the name of the file to store the numbers **/
    cout << "Enter name of file to store random number" << endl;
    cin >> file_name;

    /** now create array to store the number **/
    int random_array [random_numbers];

    /** file the array with random integers **/
    for(int i=0; i<random_numbers; i++){
        random_array[i] = random_generator -> randInt(-20, 20);
        cout << random_array[i] << endl;
    }

    /** open file and write contents of random array **/
    const char* file = file_name.c_str();
    ofstream File(file);

    /** write contents to the file **/
    for(int i=0; i<random_numbers; i++){
        File << random_array[i] << endl;
    }

    /** close the file **/
    File.close();   

    return 0;
    /** END OF PROGRAM **/
}

Answer 1

您不能在堆栈上声明大小仅在运行时已知的整数数组。但是，您可以在堆上声明这样的数组:

int *random_array = new int[random_numbers];

不要忘记在 main() 末尾添加 delete [] random_array; (以及 delete random_generator;)来释放使用分配的内存新。当您的程序退出时，该内存会自动释放，但无论如何释放它都是一个好主意(如果您的程序不断增长，很容易忘记稍后添加它)。

除此之外，您的代码看起来不错。