文件的读入和输出（目前只是适合于一行一个代码的）

#include<iostream>
using namespace std;
#include<fstream>
int main()
{
    int number[] = { 1,2,34,5,6,8 };
    ofstream outPut("test.txt");
    int length = sizeof(number) / sizeof(number[0]);
    for (int i = 0; i < length;i++)
    {
        outPut << number[i] << endl;
    }
    ifstream fInPut("test.txt");
    int num = 0, sum = 0;
    while (true)
    {
        if (fInPut >> num)
        {
            sum += num;
        }
        else {
            break;
        }
    }
    cout << sum;
    return 0;
}