Help with errors: C++

Sergei Steshenko · 07-07-2010, 11:02 AM

Quote:

Originally Posted by Wim Sturkenboom

... What the meaning is of what is in there depends on the code that you write. ...

And on the CPU architecture.

MTK358 · 07-07-2010, 12:04 PM

Quote:

Originally Posted by Sergei Steshenko

And on the CPU architecture.

At the CPU level, both instructions and data are all just bytes in memory. A certain value can be interpreted as a signed integer, integer, character, floating point number, CPU instruction, etc. only depending on how it's used.

bluegospel · 07-07-2010, 12:07 PM

Okay, my code finally compiles, but when I post to the binary file from an html form saved to the same folder there's a popup that says, "You have chosen to open "schedule_payment" (the name of my binary) which is a: Binary File from: /home/barth/cppexperiments
Would you like to save this file?"

When I save I get another popup indicating schedule_payment was downloaded. (NO OUTPUT) My only other option is cancel. Either way, my code doesn't output html as I expect it to.

Does the program have to be a cgi-script in order to output a webpage? Otherwise, why won't my program generate the one specified?

Here's the HTML & code:

Code:

<html><head>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

</head><body><form action="schedule_payment" method="post">

<basefont size="3">

Payee: <input name="payee" type="text"><br>

Description: <input name="description" type="text"><br><br>

Frequency:<br>
<input name="frequency" value="weekly" type="radio"> Weekly <br>

<input name="frequency" value="bi-weekly" type="radio"> Bi-weekly <br>
<input name="frequency" value="semi-monthly" type="radio"> Semi-monthly<br>
<input name="frequency" value="monthly" type="radio"> Monthly<br>
<input name="frequency" value="quarterly" type="radio"> Quarterly<br>
<input name="frequency" value="semi-annually" type="radio"> Semi-annually<br>
<input name="frequency" value="annual" type="radio"> Annually<br><br>

Type Payment:<br>
<input name="flux" value="fixed" type="radio"> Fixed <br>
<input name="flux" value="variable" type="radio"> variable <br><br>

Amount of payment: (leave blank if "variable" is selected above) <input name="amount" type="text"><br>
<pre><font face="Times New Roman" size="3">Date of first scheduled payment: <input name="firstpayment" type="text">  (mm/dd/yyyy)</font><br></pre>

<input value="Submit" type="submit">



</form> </body></html>

Code:

#include <iostream>
#include <cstdlib>
#include <stdlib.h>
#include <cstdio>
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include <stddef.h>

using namespace std;

int main()
{
  char* billschedContentLength = getenv("CONTENT_LENGTH");
  char* billschedBuffer;
  int nContentLength = atoi(billschedContentLength);
  

  billschedBuffer = (char*) malloc(nContentLength+1);  // allocate a buffer
  memset(billschedBuffer, 0, nContentLength+1);  // zero it out

  fread(billschedBuffer,1,nContentLength,stdin);  // get data

   cout << "Content-type: text/html" << endl << endl
   << "<html>" << endl
   << "<body>" << endl
   << "<p>" << endl
   
   <<billschedBuffer<<""<<endl

   << endl
   << "" << endl
   << "" << endl
   << "" ;


  free(billschedBuffer);

  return 0;

}

Sergei Steshenko · 07-07-2010, 12:46 PM

Quote:

Originally Posted by MTK358

At the CPU level, both instructions and data are all just bytes in memory. A certain value can be interpreted as a signed integer, integer, character, floating point number, CPU instruction, etc. only depending on how it's used.

My point is that there exist CPU architectures that natively deal with BCDs. I.e. the architectures have machine commands that perform operations on BCDs.

MTK358 · 07-07-2010, 12:48 PM

Quote:

Originally Posted by Sergei Steshenko

My point is that there exist CPU architectures that natively deal with BCDs. I.e. the architectures have machine commands that perform operations on BCDs.

I don't understand, what I said wasn't meant to counter your argument that some CPUs use BCD.

Sergei Steshenko · 07-07-2010, 12:50 PM

Quote:

Originally Posted by bluegospel

...
Does the program have to be a cgi-script in order to output a webpage? Otherwise, why won't my program generate the one specified?
...

You are doing it wrong methodologically. You first need to call your program stand-alone providing it with the needed inputs and verifying that it produces the required outputs.

There is absolutely no place for any kind of pop-up windows in the suggested verification scenario.

bluegospel · 07-07-2010, 12:54 PM

When you refer to "cpu architecture" do you mean the processor by itself (its on-board cache & registers included), or also the processor's platform to some extent (the machine's rom, busses, etc.)? Does the physical processor have built in instructions, or are they mostly or in part external?

bluegospel · 07-07-2010, 12:58 PM

So I should edit the program such that it doesn't depend on input from a webpage, providing all the input directly, or via a shell prompt.

MTK358 · 07-07-2010, 01:05 PM

Quote:

Originally Posted by bluegospel

When you refer to "cpu architecture" do you mean the processor by itself (its on-board cache & registers included), or also the processor's platform to some extent (the machine's rom, busses, etc.)? Does the physical processor have built in instructions, or are they mostly or in part external?

All the instructions are internal to the CPU.

Sergei Steshenko · 07-07-2010, 01:09 PM

Quote:

Originally Posted by bluegospel

When you refer to "cpu architecture" do you mean the processor by itself (its on-board cache & registers included), or also the processor's platform to some extent (the machine's rom, busses, etc.)? Does the physical processor have built in instructions, or are they mostly or in part external?

No machine ROM/buses.

Physical processor does have built-in instructions, but look up on the WEB "CPU microcode".

Sergei Steshenko · 07-07-2010, 01:12 PM

Quote:

Originally Posted by bluegospel

So I should edit the program such that it doesn't depend on input from a webpage, providing all the input directly, or via a shell prompt.

You shouldn't edit the program. You should create test environment which imitates real world. E.g. if inputs are given to the program through 'argc', 'argv', give them on command line; if through environment variables, set environment variables first, etc.

I.e. you first need to understand how the program is connected to the real world - regardless of the language your program is written in.

bluegospel · 07-07-2010, 01:16 PM

Are they burned somewhere? Approximately how many instructions? I presume these all either send information to, or get information from, a peripheral or registers, and, or else, they perform some kind of operation on information in its registers, based on its instruction set & corresponding instructions from various programs.

Sergei Steshenko · 07-07-2010, 01:18 PM

Quote:

Originally Posted by bluegospel

Are they burned somewhere? Approximately how many instructions? I presume these all either send information to, or get information from, a peripheral or registers, and, or else, they perform some kind of operation on information in its registers, based on its instruction set & corresponding instructions from various programs.

http://en.wikipedia.org/wiki/Central_processing_unit .

bluegospel · 07-07-2010, 01:44 PM

Again, pardon my illiteracy. Are you saying there's always some way to execute your program, passing input to it in a way other than the way executed in run-time reality? So that, if input comes from an environment variable, I can set the environment variable manually and execute the program that way, or if from a call w/ arguments, I can somehow bypass executing the program its ordinary way, in such a way as to test it?

Sergei Steshenko · 07-07-2010, 01:52 PM

Quote:

Originally Posted by bluegospel

Again, pardon my illiteracy. Are you saying there's always some way to execute your program, passing input to it in a way other than the way executed in run-time reality? ...

For your kind of domain/activity - yes. Luckily, your program is single-threaded and non-real-time.