C++文件操作如何一次性读取或写入一个结构体大小！
C语言一次性读取一个结构大小没有问题！但是c++如何实现那个对象是实现改功能的呢？:cry 你是想用文件流的read或write之类的函数么？下面是cppreference.上的示例代码：
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <cstdint>
int main()
{
// read() is often used for binary I/O
std::string bin = {'\x12', '\x12', '\x12', '\x12'};
std::istringstream raw(bin);
std::uint32_t n;
raw.read(reinterpret_cast<char*>(&n), sizeof n);
std::cout << std::hex << std::showbase << n << '\n';
// prepare file for next snippet
std::ofstream os("test.txt", std::ofstream::binary);
for (unsigned i = 0; i < 10; i++) { // prepare stream
os << "abcd" << i << "\n";
}
os.close();
// read entire file into string
std::ifstream is("test.txt", std::ifstream::binary);
if (is) {
// get length of file:
is.seekg(0, is.end);
int length = is.tellg();
is.seekg(0, is.beg);
std::string str;
str.resize(length, ' '); // reserve space
char* begin = &*str.begin();
is.read(begin, length);
is.close();
std::cout << str << "\n";
} else {
std::cout << "Could not open test.txt\n";
}
}
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