C++ 怎么从txt文件需要的位置开始读取数据，并存入数组

[adnana]

一个txt文档，前面部分是关于设置的，不需要读取，要读取的是在中间部分是输出结果，要做的是把一行里的5个数据存入不同的数组中，求高手指点
Step Time XX0001 XX0008 XX0009 XX0010

0 0.0 0.0 8284.51544 -4164.7537 -4119.7617
500 .25E-3 .182949848 8261.02951 -3589.5704 -4670.9102
1000 .5E-3 .759112568 8186.71113 -2991.8512 -5192.5825
1500 .75E-3 1.72350195 8062.20225 -2375.4681 -5681.5635
2000 .1E-2 3.06911774 7888.49492 -1744.336 -6134.9514
2500 .00125 4.80059818 7666.83464 -1102.3032 -6550.1294
3000 .0015 6.9776973 7398.65209 -453.017 -6924.7017
3500 .00175 9.48312771 7085.54949 199.505165 -7256.605
4000 .002 11.808714 6729.23348 851.116104 -7544.9232
4500 .00225 13.7718778 6331.47043 1497.51633 -7787.6709
5000 .0025 15.3715757 5894.17974 2134.59477 -7982.6596
5500 .00275 16.6155607 5419.61819 2758.2452 -8128.0166

[a707000646]

int fseek( FILE *stream, long offset, int origin );
Parameters
stream
Pointer to FILE structure
offset
Number of bytes from origin
origin
Initial position
Libraries
All versions of the C run-time libraries.

Return Values
If successful, fseek returns 0. Otherwise, it returns a nonzero value. On devices incapable of seeking, the return value is undefined.

Remarks
The fseek function moves the file pointer (if any) associated with stream to a new location that is offset bytes from origin. The next operation on the stream takes place at the new location. On a stream open for update, the next operation can be either a read or a write. The argument origin must be one of the following constants, defined in Stdio.h:

SEEK_CUR
Current position of file pointer
SEEK_END
End of file
SEEK_SET
Beginning of file

[turing-complete]

内存映射

[a707000646]

不好意思楼主
按照你的问题
那应该是用循环,然后用fscanf加站位字符串去读取

[hongwenjun]

// readfile.cpp

#include <wx/textfile.h>

int main(int argc, char **argv)
{

  wxTextFile file(wxT("test.c"));

  file.Open();

  wxPrintf(wxT("Number of lines: %d\n"), file.GetLineCount());
  wxPrintf(wxT("First line: %s\n"), file.GetFirstLine().c_str());
  wxPrintf(wxT("Last line: %s\n"), file.GetLastLine().c_str());

  wxPuts(wxT("-------------------------------------"));

  wxString s;

  for ( s = file.GetFirstLine(); !file.Eof(); 
      s = file.GetNextLine() )
  {
       wxPuts(s);
  }

  file.Close();
}

使用 wxTextFile 库，可以自由输出 文本文件里的任意行

Output

Number of lines: 8
First line: #include 
Last line: }
-------------------------------------
#include <glib.h>
#include <glib/gstdio.h>

int main() {

g_mkdir("/home/vronskij/test", S_IRWXU);

}

[hongwenjun]

没注意看错题目了。

可以 设置一个 数据开始标记
比如 #date_start
然后从这个接一下来的一行才开始输出数据

[zzcmx2008]

ifstream打开文件，
循环getline读取每一行的内容，进行提取，知道getline返回失败

[柯大侠爱喝水]

1：循环读fscanf()出每一行

2：把其存入char数组，用strstr（）找空格，截取出五个数字串

3：依次把五个数值串找出来，再转为数值存入你说的数组

[柯大侠爱喝水]

具体转化自己实现，c中有函数的

[hongwenjun]

#include <iostream>
#include <string>
#include <algorithm>
#include <sstream>

using namespace std;

int main()
{
    stringstream  oss("Step Time XX0001 XX0008 XX0009 XX0010    \n"
                      "1 2 3 4 5 6 \n"
                      "1 2 3 4 5 6 \n"
                      "1 2 3 4 5 6 \n"
                      "1 2 3 4 5 6 \n"
                      "1 2 3 4 5 6 \n"

                     );
    string Title;  // 标题行
    int step; //  步数
    double data[5];  // 装载数据
    int cnt = 0;     // 数据计数

    while (getline(oss, Title) && (Title.find("Step") != string::npos))
        ; // 跳过开头标题

    while (oss) {   // 读取一行数据
        oss >> step;
        oss >> data[0]  >> data[1]  >> data[2]
            >> data[3]  >> data[4] ;
        cnt++;
    }
    // 测试一行
    cout << data[0]  << data[1]  << data[2]
         << data[3]  << data[4] ;
    return 0;
}

[动感超哥]

用偏移量 也可以撒