使用 C++ 将整数写入二进制文件？
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Writing integer to binary file using C++?
提问by eqagunn
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.
我有一个非常简单的问题，这对我来说很难，因为这是我第一次尝试使用二进制文件，我不太了解它们。我想要做的就是将一个整数写入一个二进制文件。
Here is how I did it:
这是我如何做到的：
#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;
}
Could you please tell me if I did something wrong, and what?
如果我做错了什么，你能告诉我吗？
The part that is giving me trouble is line with file.write, I don't understand it.
给我带来麻烦的部分是file.write，我不明白。
Thank you in advance.
先感谢您。
回答by
The part that is giving me trouble is line with file.write, I don't understand it.
给我带来麻烦的部分是file.write，我不明白。
If you read the documentation of ofstream.write()method, you'll see that it requests two arguments:
如果您阅读ofstream.write()方法文档，您会看到它需要两个参数：
a pointer to a block of datawith the content to be written;
an integer value representing the size, in bytes, of this block.
一个指针的数据块与要写入的内容;
一个整数值，表示此块的大小（以字节为单位）。
This statement just gives these two pieces of information to ofstream.write():
该声明仅将这两条信息提供给ofstream.write()：
file.write(reinterpret_cast<const char *>(&num), sizeof(num));
&numis 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).
&num是数据块的地址（在这种情况下只是一个整数变量），sizeof(num)是该块的大小（例如，在 32 位平台上为 4 个字节）。
