我的二进制文件有问题。我想创建一个二进制文件,其中会有许多版本和程序的颠覆。然后,从该文件中我想通过读取第一个sizeof(uint16_t)咬,然后再次读取sizeof(uint16_t)来读取内部的内容。但我不知道该怎么做。 (我甚至都不亲近)
#include <iostream>
#include <fstream>
#include <stdint.h>
using namespace std;
void saving_uint16_t(uint16_t number);
uint16_t reading_uint16_t();
int where = 0;
int main() {
const uint16_t number_version = 2;
cout << "Version: " << number_version << endl;
cout << "Saving number..." << endl;
saving_uint16_t(number_version);
const uint16_t number_subversion = 1;
cout << "Subversion: " << number_subversion << endl;
cout << "Saving number..." << endl;
saving_uint16_t(number_subversion);
cout << "Read numbers:\nVersion: " << reading_uint16_t() << "\nSubversion: " << reading_uint16_t() << endl << endl;
return 0;
}
void saving_uint16_t(uint16_t number) {
ofstream data("numbers.bin", ios::app | ios::binary);
data.write(reinterpret_cast<char*>(&number), sizeof(uint16_t));
}
uint16_t reading_uint16_t(){
ifstream data("numbers.bin", ios::binary);
data.seekg(where);
where = where + 16;
uint16_t result;
data.read(reinterpret_cast<char*>(&result), sizeof(uint16_t));
return result;
}
我真的很新,我不知道该用什么。
输出:
Version: 3
Saving number...
Subversion: 7
Saving number...
Read numbers:
Version: 3
Subversion: 3
然后我改变了数字但仍然得到了:
Version: 2
Saving number...
Subversion: 1
Saving number...
Read numbers:
Version: 3
Subversion: 3
应该是:
Version: 2
Saving number...
Subversion: 1
Saving number...
Read numbers:
Version: 2
Subversion: 1
我想补充一点,我的目标是创建一个二进制文件,其中有两个uint16_t变量,然后从文件中单独读取它们。所以我可以写那个版本:(第一个uint16_t),Subversion :(第二个uint16_t)
答案 0 :(得分:0)
因此,通过查看提取numbers.bin中所有uint16_t
的函数,可能会改善您的理解。假设所有numbers.bin包含的是uint16_t
s,那么你可以这样做:
ifstream data("numbers.bin", ios_base::binary | ios_base::ate); // Starting at the end of the stream for sizing
const auto count = data.tellg() / sizeof(uint16_t); // tellg will report the number of characters in the file, sizeof(uint16_t) the numberof characters required to store a uint16_t, thus the division will give us the number of uint16_ts in numbers.bin
vector<uint16_t> numbers(count); // Allocate storage for all the uint16_ts in numbers.bin
data.seekg(0U, ios_base::beg); // Move the input position indicator to the beginning of the file for reading
data.read(reinterpret_cast<char*>(numbers.data()), count * sizeof(uint16_t)); // Slurp the file into numbers
与访问numbers.bin的特定元素类似,我们需要相应地设置位置:
ifstream data("numbers.bin", ios_base::binary); // Starting at the beginning of the file
const auto where = 2U; // This offset will be 0 based
uint16_t number; // Allocate storage for the element at where
data.seekg(where * sizeof(uint16_t)); // Move the input position indicator to the specified uint16_t
data.read(reinterpret_cast<char*>(&number), sizeof(number)); // Read the element into number