Question

以下小程序应该创建一个二进制文件，写入6 uint（typedef＆＃39; ed as unsigned int），然后从同一个文件中读取并打印数据。

#include <iostream>
#include <fstream>
#include <string>

typedef unsigned int uint;

using namespace std;

int main(int argc, char* argv[])
{
    string usr = [my username];
    string szFile = "C:/Users/" + usr + "/iotest.bin";
    cout << "File Streaming Test\n" << sizeof(uint) << "\n\n";

    ifstream inFile = ifstream(szFile, ios_base::in | ios_base::binary);

    if (inFile.fail()) {
        // file probably DNE, create it and write some data to it
        inFile.clear();

        // first, close the input stream
        // so the output stream can be opened
        inFile.close();

        // open the output stream
        ofstream outFile = ofstream(szFile, ios_base::out | ios_base::trunc | ios_base::binary);
        // make sure these are written as uint
        uint zero = 0;
        uint one = 1;
        uint two = 2;

        // write the data
        outFile << two << two << zero << one << one << zero;

        // flush and close the output stream
        outFile.flush();
        outFile.close();
    }

    // if we had to create the file,
    // then reopen the input stream
    if (!inFile.is_open())
        inFile.open(szFile, ios_base::in | ios_base::binary);

    // read 6 uint from the file
    uint arr[6];
    for (int i = 0; i < 6; i++) {
        inFile >> arr[i];
        cout << arr[i] << endl;
    }

    // pause
    while (cin.get() != '\n');

    // inFile auto-closes when it goes out of scope
    return 0;
}

当我运行程序一次时，它会生成以下输出：

File Streaming Test
4

220110
3435973836
3435973836
3435973836
3435973836
3435973836

第二次运行程序（检查文件浏览器中确实存在该文件后）会生成相同的输出。 Windows（文件浏览器）表示创建的文件大小只有6个字节，大小应该是6 * 4 = 24个字节。它就像outFile只是写了我给它的一部分。在一个uint中读取220110是奇怪的，因为它匹配我写的六个数字，但二进制表示不会像这样连接数字。

二进制流写入1个字节而不是4个字节

0 个答案: