c++ - 读取和写入 USACO 文件

Question

我正在为 USACO 编写代码，但文件的读写不起作用。我正在尝试读取第一个文件行并将其存储为整数。后续行将被读取并存储到数组中以执行计算。我认为这个问题与 fopen 有关。我总是收到中止窗口，上面写着stream.valid()

这是代码_

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// USACO MARATHON.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "stdio.h"
#include "stdlib.h"


int main()
{
    FILE *infp;
    FILE *outfp;
    int num_points = 0;
    int x[] = { 0 };
    int y[] = { 0 };
    int total_dist = 0;
    int i;
    infp = fopen("C:\\Users\\jalen\\documents\\visual studio 2017\\Project\\real_marathon\\real_marathon\\Debug\\marathon.in", "r");
    outfp = fopen("marathon.out", "w");
    /*if ((infp = fopen("marathon.in", "r")) != NULL)
    {
        fscanf(infp, "%d", num_points);
    }*/

        num_points = fgetc(infp);

    for (i = 0; i < num_points; i++)
    {
        fscanf(infp, "%d %d", &x[i], &y[i]);

    }
    for (i = 1; i < num_points; i++)
    {
        int total_distance = abs((x[i] - x[i - 1])) + abs((y[i] - y[i - 1]));
    }
    int max_skip = 0;
    for (i = 1; i < num_points - 1; i++)
    {
        int dont_skip = abs((x[i + 1] - x[i])) + abs((x[i] - x[i - 1])) + abs((y[i + 1] - y[i])) + abs((y[i] - y[i - 1]));
        int skip = abs((x[i + 1] - x[i - 1])) + abs((y[i + 1] - y[i - 1]));
        int z = dont_skip - skip;
        max_skip = z;
    }
    int output = total_dist - max_skip;
    fprintf(outfp, "%d\n", output);
    fclose(infp);
    fclose(outfp);
    return 0;
}

Answer 1

我建议使用 ofstream 和 ifstream:如果我的代码显示“文件名”，请替换为 USACO 问题陈述中给出的文件名。 fin 和 fout 与 cin 和 cout 类似，只是 fin 和 >fout 读取并打印到输入/输出文件。

#include <fstream>

using namespace std;

ofstream fout("filename.out");
ifstream fin("filename.in");

int main()
{
    int N;
    fin >> N;
    fout << N << endl;
}