Question

我正在尝试将此C ++程序移植到vb.net。

我大部分时间都在工作，但是我一直坚持（我希望！）小事。

这是C ++代码，由electronics.stackexchange用户Harry Svensson友情提供 - 完整帖子here

#include <iostream>
#include <fstream>

using namespace std;

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

  if(argc!=2){
      cout << "Drop a file on me or"<<
              "call me from the command line with one argument.\n\n";
      //cin.get();//pause, useful for when you drop a file onto the exe.
      return 1;
  }else{
    cout << "You rang?\n\n";
  }


  string suffix(argv[1]);//convert to string

  if(suffix.length()<5){
    //bad names are: "t", "xt", "txt", ".txt"
    //good names are: "a.txt" or "abc.txt"
    cout << "Doesn't look good Sonny," <<
            " give me a file on the format of \"*.txt\".\n\n";
    //cin.get();//pause, useful for when you drop a file onto the exe.
    return 1;
  }else{
    cout << "The length checks out.\n\n";
  }

  suffix.erase(0,suffix.length()-3);

  if(suffix!="txt"){
    cout << "Accepted type is \"txt\", yours is \"" << suffix << "\"\n\n";
    //cin.get();//pause, useful for when you drop a file onto the exe.
    return 1;
  }else{
    cout << "Got a file of the correct type. Let's proceed.\n\n";
    cout << "===========================================\n\n";
  }



  ifstream file(argv[1]);//let's finally open the file
  string row; //contains row of document, with a ',' as a delimiter
  unsigned int samples, 
           sample_rate, 
           ground,data, 
         previous_data,
       zero_crossing=0,
                 end=0,
              start=-1;

  //First get the number of samples and sample rate.

  getline(file,row,'-');//throw away first part
  file >> samples; //acquired samples.
  cout << "Number of samples = " << samples << endl;    
  getline(file,row,',');//skip
  getline(file,row,',');//skip

  file >> sample_rate; //acquired the sample rate
  cout << "Sample rate = " << sample_rate << endl;

  getline(file,row,',');//skip
  getline(file,row,',');//skip

  file >> ground;
  cout << "Ground level = " << ground << endl << endl;

  //Okay, now we just need to read the rest of the document     
  for(unsigned int i=0;i<samples;++i){
    getline(file,row,',');//skip the "Data0" text
    previous_data=data;
    file >> data;


    if(data<ground && previous_data>=ground){
    //we've just passed ground and we're going upwards.
      if(start==-1){
        //is this the first time we've came across this zero crossing?
        start=i;    
      }else{
        zero_crossing++;
        //this is a potential stop
        end=i;  
      }
    }
  }

  double mean_period = (end-start)/((double)zero_crossing);
  double frequency = sample_rate / mean_period;


  cout << "First occurance of a negative edge = " << start << endl;
  cout << "Last occurance of a negative edge = " << end << endl;
  cout << "Length between those two = " << end-start << endl;
  cout << "Number of crossings detected = " << zero_crossing << endl;
  cout << "Mean length per period = " << mean_period << endl;
  cout << "Frequency = " << frequency << endl;


  cout << endl << endl;
  //cin.get();//pause, useful for when you drop a file onto the exe.
  return 0;
}

这是我到目前为止的vb.net代码：

Dim sample_rate, data, previous_data As Integer
Dim zero_crossing As Integer = 0
Dim dataEnd As Integer = 0
Dim start As Integer = -1
Dim ground As Integer = Str(DataBuffer1(2))
Dim j As Integer = 0

For i As UInteger = 0 To 4096 - 1
    list.Add(Str(DataBuffer1(i + 3))) ' required to calculate RMS values
    ListBox1.Items.Add(Str(i) + Chr(9) + Chr(9) + Str(DataBuffer1(i + 3)))
    samples = i
    previous_data = data
    data = (Str(DataBuffer1(i + 3)))
    If data < ground AndAlso previous_data >= ground Then
        If start = -1 Then
            start = i
        End If
    Else
        zero_crossing += 1
        dataEnd = i
    End If

Next

Dim mean_period As Double = (dataEnd - start) / (zero_crossing)
Dim frequency As Double = sample_rate / mean_period
MsgBox("Period is" & " " & mean_period & " " & "Frequency is" & " " & frequency)
TextBox12.Text = frequency

我似乎在转换C ++部分时遇到了问题;

zero_crossing++;
end=i;

到vb.net;

zero_crossing += 1
dataEnd = i

似乎vb.net代码没有＆＃34;拯救＆＃34;当达到最后的零交叉时。

C ++代码遍历循环81次 - 但是vb.net代码遍历整个4095次。

C ++程序的输出显示样本为4096

Number of samples = 4096
Sample rate = 25000000
Ground level = 127
First occurance of a negative edge = 40
Last occurance of a negative edge = 4090
Length between those two = 4050
Number of crossings detected = 81
Mean length per period = 50
Frequency = 500000

继续循环问题：

  for(unsigned int i=0;i<samples;++i){
    getline(file,row,',');//skip the "Data0" text
        cout << "WIBBLE" << endl;

./parse velleman-500khz.txt > output

cat output|grep WIBBLE |wc -l
4097

所以主外环实际上循环了4097次......

然而此时它循环832次：

if(data<ground && previous_data>=ground){
    cout << "WIBBLE" << endl;

cat output|grep WIBBLE |wc -l
83

有人可以帮忙吗？

Answer 1

zero_crossing位于错误的位置 - 如果start = -1＆＃39;它应该是＆else; - 在下面的片段中更正。

        If start = -1 Then
                ' this also outputs the same values as c++
            start = i
        Else
                ' it's here that it all seems to go wrong. - that's because it was in the wrong place
            zero_crossing += 1
            dataEnd = i
        End If
    End If
Next

将简单程序从C ++移植到vb.net

1 个答案: