[英]Calculating frequency of symbols of binary file in c# not working but working for equivalent c++ code
我正在尝试计算c#
中的二进制文件中符号的频率,我已经在c ++中做到了,而且效果很好,我已经从c ++切换到c#,因为我必须在c#中实现相同的频率。
注意:我不必使用LUT /数组,而仅需使用链表。
frequency
是指符号的重复数, symbols
是指如果我们使用xxd -b BinaryFile.bin
查看二进制文件,那么我们将得到很多0
和1
的8 bits
组合。 因此,每个符号重复多少次是它的频率。
现在,我如何尝试做到这一点:我在c#
通过在终端使用mono filename.exe BinaryFile.bin
并在notepad ++内用filename编写的代码来实现它。
逻辑:如果不重复,则读取BinaryFile中的每个符号,然后将其添加到链接列表的末尾;如果重复,则增加其频率。 我重复完整的二进制文件。
码:
c#的代码(完整):(无法正常工作,我指出了代码中包含部分内容的问题,我放入了完整代码,因为可能您会需要它):
////Problem containing part starts here ////////
public Huffman(string[] args) //called from MyClass
{
Node tree = null;
int counter = 0;
using(var stream = new BinaryReader(System.IO.File.OpenRead(args[0])))
{
while (stream.BaseStream.Position < stream.BaseStream.Length)
{
int processingValue = stream.ReadByte();
Node ppt, pt, temp;
bool is_there = false;
ppt = pt = tree;
while (pt != null)
{
if (pt.symbol == processingValue)
{
pt.freq++;
is_there = true;
break;
}
ppt = pt;
pt = pt.next;
}
if (is_there == false)
{
temp = new Node();
temp.symbol = processingValue;
temp.freq = 1;
temp.left = null;
temp.right = null;
temp.next = null;
temp.id = (++total_nodes);
temp.is_processed = 0;
if (tree == null)
{
tree = temp;
}
else
{
ppt.next = temp;
}
//The same check/debugging which i was doing in c++ to know what symbol and freq contains but they contains different values.
//And the output of both c#/c++ are different where as it was supposed to be same.
Node chc = tree;
while (chc != null)
{
Console.WriteLine(" sym: " + chc.symbol);
Console.WriteLine(" freq: " + chc.freq);
chc = chc.next;
}
}
}
stream.Close();
}
}
////Problem containing part Ends here ////////
C ++和c#的输出之间的区别:
(1)当我显示c ++的输出时,它可以正常工作;当我看到我在代码中编写的代码部分以调试/检查终端上的输出时,即表明代码正确执行。 而C#中相同的调试代码与C ++不会显示相同的输出。 之所以这样做,是因为这两个用于打印“符号”和“频率”的代码都保存在程序中的同一位置。
(2)C#的输出使我感到,虽然在c#中执行循环的次数比在c ++中执行循环的次数少,因为在c#输出终端中没有显示大量的频率和符号重复。 请查看两者的输出:
在终端的C#输出:
hp@ubuntu:~/Desktop/$ mono check1.exe out.bin
sym: 0
freq: 1
sym: 0
freq: 200
sym: 1
freq: 1
sym: 0
freq: 200
sym: 1
freq: 198
sym: 2
freq: 1
sym: 0
freq: 200
sym: 1
freq: 198
sym: 2
freq: 195
sym: 3
freq: 1
sym: 0
freq: 200
sym: 1
freq: 198
sym: 2
freq: 195
sym: 3
freq: 189
sym: 4
freq: 1
hp@ubuntu:~/Desktop/
而c++
的输出是:(此处计数器的值实际上是从“ 0”开始的(不是“ 196”)),但是由于文件较大,所以输出无法显示完整的输出,因此终端很大,无法显示全部,它仅在最后显示输出)
hp@ubuntu:~/Desktop/$ ./filename out.bin
//Counter starts from "0" but terminal is not able to show all.So doing from "196"
counter: 196
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 1
counter: 197
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 2
counter: 198
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 3
counter: 199
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 4
counter: 200
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 5
counter: 201
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 6
counter: 202
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 7
counter: 203
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 8
counter: 204
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 9
counter: 205
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 10
counter: 206
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 11
counter: 207
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 12
counter: 208
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 13
counter: 209
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 14
counter: 210
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 15
counter: 211
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 16
counter: 212
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 17
counter: 213
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 18
counter: 214
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 19
counter: 215
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 20
counter: 216
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 21
counter: 217
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 22
counter: 218
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 23
counter: 219
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 24
counter: 220
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 25
counter: 221
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 26
counter: 222
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 27
counter: 223
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 28
counter: 224
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 29
counter: 225
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 30
counter: 226
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 31
counter: 227
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 32
counter: 228
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 33
counter: 229
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 34
counter: 230
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 35
counter: 231
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 36
counter: 232
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 37
counter: 233
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 38
counter: 234
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 39
counter: 235
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 40
counter: 236
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 41
counter: 237
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 42
counter: 238
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 43
counter: 239
sym: 0
freq: 50
sym: 1
freq: 50
sym: 2
freq: 48
sym: 3
freq: 48
sym: 4
freq: 44
问题:
(1)为什么c#代码显示的输出与c ++不同? 甚至我也品尝过相同的BinaryFile(以我的情况为out.bin)。
(2)您能帮助我解决这个问题吗? 太谢谢了
我可能完全误解了……您是否只想知道指定文件中每个字节值(0..255)的出现次数?
如果是这样,一个简单的方法是这样的:
var counts = new int[256]; // Assumes files aren't longer than 2GB.
string filename = "<Your filename goes here>";
foreach (byte b in File.ReadAllBytes(filename)) // Will run out of memory
++counts[b]; // for very large files!
for (int i = 0; i < counts.Length; ++i)
Console.WriteLine("Symbol {0} occurred {1} times.", i, counts[i]);
但是,这比您正在做的事情简单得多,我觉得我一定会误会...。
[编辑]
我无法修复您的原始代码,但这是一个示例程序,该程序使用链接列表来解决问题:
using System;
using System.IO;
namespace ConsoleApp1
{
public sealed class Node
{
public byte Symbol { get; set; }
public int Count { get; set; }
public Node Next { get; set; }
}
sealed class Program
{
private void run()
{
var linkedList = new Node();
string filename = @"C:\Test\t.cs";
foreach (byte symbol in File.ReadAllBytes(filename))
addSymbol(symbol, linkedList);
for (int symbol = 0; symbol < 256; ++symbol)
{
int count = countForSymbol((byte)symbol, linkedList);
Console.WriteLine("Symbol {0} occurred {1} times.", symbol, count);
}
}
private static void addSymbol(byte symbol, Node head)
{
Node last = head;
while (head != null)
{
last = head;
if (head.Symbol == symbol)
{
++head.Count;
return;
}
else
{
head = head.Next;
}
}
last.Next = new Node
{
Symbol = symbol,
Count = 1
};
}
private int countForSymbol(byte symbol, Node head)
{
while (head != null)
{
if (head.Symbol == symbol)
return head.Count;
else
head = head.Next;
}
return 0;
}
private static void Main()
{
new Program().run();
}
}
}
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