问题描述

我有一个非常简单的问题，这对我来说很困难，因为这是我第一次尝试使用二进制文件，但我不太了解它们.我要做的就是将一个整数写入二进制文件.

I have a very simple question, which happens to be hard for me since this is the first time I tried working with binary files, and I don't quite understand them. All I want to do is write an integer to a binary file.

我是这样做的:

#include <fstream>
using namespace std;
int main () {
    int num=162;
    ofstream file ("file.bin", ios::binary);
    file.write ((char *)&num, sizeof(num));
    file.close (); 
    return 0;
}

如果我做错了什么，你能告诉我吗?

Could you please tell me if I did something wrong, and what?

给我带来麻烦的部分是file.write，我不明白.

The part that is giving me trouble is line with file.write, I don't understand it.

提前谢谢你.

推荐答案

给我带来麻烦的部分是file.write，我没有明白了.

The part that is giving me trouble is line with file.write, I don't understand it.

如果您阅读 ofstream.write() 方法的文档，您会看到它需要两个参数:

If you read the documentation of ofstream.write() method, you'll see that it requests two arguments:

1. 一个指向数据块的指针，其中包含要写入的内容；

1. a pointer to a block of data with the content to be written;

一个整数值，表示此块的大小(以字节为单位).

这条语句只是将这两条信息提供给ofstream.write():

This statement just gives these two pieces of information to ofstream.write():

file.write(reinterpret_cast<const char *>(&num), sizeof(num));

&num 是数据块的地址(在这种情况下只是一个整数变量)，sizeof(num) 是这个块的大小(例如在 32 位平台上为 4 个字节).

&num is the address of the block of data (in this case just an integer variable), sizeof(num) is the size of this block (e.g. 4 bytes on 32-bit platforms).

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