[C++][windows][原创]文件读写逐行读文件

#include <fstream>
#include <iostream>
#include <vector>
#include <string>
using namespace std;
std::vector<std::string> ReadLines(std::string& filename)
{
		std::ifstream file(filename);
		string str;
		std::vector<std::string> lines;
		while (getline(file, str)) {
			lines.push_back(str);
		}
		
		return lines;

}
std::string ReadFile(std::string& filename)
{
	std::ifstream file;
	//以只读方式打开文件
	file.open(filename, std::ios::in);
	//指针定位到文件末尾
	file.seekg(0, std::ios::end);
	int fileLength = file.tellg();
	//指定定位到文件开始
	file.seekg(0, std::ios::beg);
	char* buffer = new char[fileLength + 1];
	file.read(buffer, fileLength);
	buffer[fileLength] = '\0';
	std::string content = buffer;
	if (buffer) {
		delete[] buffer;
	}
	file.close();
	return content;
}
void WriteFile(std::string content, std::string savefile)
{
        std::ofstream out(savefile);
        if (out.is_open())
        {
            out << content;
            out.close();
        }
}


int main()
{
	std::string file = "result.txt";
    WriteFile("123", file);
	std::string res = ReadFile(file);
	std::cout << res << "\n";
	std::vector<std::string> lines = ReadLines(file);
	std::cout << lines.size() << "\n";
    getchar();
	return 0;
}