C File read getchar yields random EOF after 32KB

See also questions close to this topic

• Frequency of digits in my 2-D array not outputting correctly

  My goal is if for example I would make the size of my array 2x6 and I would input values (0, 1, 2, 3, 4, 5) for row 1 and values (0, 1, 6, 7, 8, 9) for row 2 it would output: Digit 0 occurs 2 times Digit 1 occurs 2 times Digit 2 occurs 1 times etc. but it doesn't. Here is my code:

  #include <stdio.h>
  
  int main(void)
  {
   int row, col, N, M, count, row1, col1;
  
   printf("This program counts occurrences of digits 0 through 9 in an NxM array.\n");
   printf("Enter the size of the array (Row Column): ");
   scanf("%d %d", &N, &M);
  
   int digits[N][M], freq[N][M];
  
   for (row = 0; row < N; row++){ 
    printf("Enter row %d: ", row);
    for (col = 0; col < M; col++){
     scanf("%d", &digits[row][col]);
    }
   } 
  
   freq[row][col] = -1;
  
   for (row = 0; row < N; row++){
    count = 1;
    for (row1 = row + 1; row1 < N; row1++){
     for (col = 0; col < M; col++){
      for (col1 = col + 1; col1 < M; col1++){
       if (digits[row][col] == digits[row1][col1]){
        count++;
        freq[row1][col1] = 0;
       }
      }
      if (freq[row][col] != 0){
       freq[row][col] = count;
      }
     } 
    } 
   }
  
   printf("Total counts for each digit:\n");
   for (row = 0; row < N; row++){
    for (col = 0; col < M; col++){
     if (freq[row][col] != 0){
      printf("Digit %d occurs %d times\n", digits[row][col], freq[row][col]);
     }
    } 
   } 
  
   return 0;
  }
  
• Can't print char** outside of getline() while loop

  Trying to read a file from commandline argument with getline() and store into char**, but when I try to access the data inside like using printf(), it prints nothing. Although printf() works fine within the while loop after each getline().

  Any help is greatly appreciated!

  int main (int argc, char* argv[])
  {
      //open file
      FILE *stream = NULL;
      char *line = NULL;
      size_t len = 0;
      ssize_t nread;
      if (argc != 2)
      {
          fprintf(stderr, "Usage: %s <file>\n", argv[0]);
          exit(EXIT_FAILURE);
      }
      stream = fopen(argv[1], "r");
      if (stream == NULL)
      {
          perror("fopen");
          exit(EXIT_FAILURE);
      }
  
      //read file line by line
      char ** input = NULL;
      int i = 0;
      int j = 0;
      while ((nread = getline(&line, &len, stream)) != -1)
      {
          j++;
          input = (char **)realloc(input, sizeof(char*) * j);
          input[i] = (char *)malloc(sizeof(char) * strlen(line));
          input[i] = line;
  
          //print each line (PRINTS FINE)
          printf("%s",input[i]);
          i++;
      }
  
      //print each line outside of while loop (PRINTS NOTHING)
      for (int z = 0; z < j ; z++)
      {
          printf("%s",input[z]);
      }
  }
  

  Welcome to try with any .txt file like this

  ./a.out input.txt
  
• How to go to definition inside comment area in VScode

  I remember it's possible to use goto definition/declaration within the comment area on some older version previously, but I cannot do it in the recent version.

  Are there any settings to do so?

  // myFunction();   -> CANNOT go to definition on this line
  
  myFunction();      -> CAN go to definition on this line
  

  Version: 1.28.1 on windows x64

  language: C
• Multiprocessing for robust simulation on webserver

  The problem: Create a back-end service for a web application that runs physical simulations. In the front-end, some parameters can be set and submitted to the server, which will run a simulation. The results of the simulation are sent to the client for analysis.

  The question: What is a good architecture to solve this problem? "Good" meaning robust, and simple to set up, maintain, and scale. I am coming from scientific computing and therefore have not much experience with such architectural questions. I thought about:

  1. All-In-One: Implement the web server in the same language the simulation runs, and manage the multi-processing in this "single environment" as well.

  2. Separate web server and workers: Implement the (asynchronous) web server in a suitable language, calling workers in their own processes (in another language). The server would also have to implement a simple load-balancing of the workers (i.e. just wait until one is free again). Use inter-process communication of some sort (gRPC, ZeroMQ, ...).

  3. Reverse-Proxy: Use a "pure" reverse-proxy server (e.g. Nginx) as load balancer above the workers, each running its own local (synchronous) web server.

  4. Docker: Create containers for the workers, and scale and load-balance them using docker-compose.

  Relevant information:

  • One simulation takes up to several seconds (on a single CPU core).
  • The server will be a virtual one (either on premise or in the cloud); for which the number of CPU's will be increased if/as the load increases.
  • Obviously, the number of "simulation workers" should scale up accordingly (preferably automatically, but not mandatory).
  • It could happen that a simulation does crash. It is not clear yet how severe such crashes can be (i.e. whether all errors can be catched or if e.g. segfaults may happen).
  • Currently, the simulation is implemented in Python (3.6), possibly using Numba JIT for speed-up, but could be ported to Julia (naturally faster).

  Thanks for any advice, both "best practices" as well as "do not do it this way" are welcome!
• POSIX like mutexes in WIN32

  Is there any equivalent of POSIX mutexes in Win32 ?

  i need mutex modes (Recursive, Error Check) in Win32 named mutexes, but there is no way to use them on Win32.

  or is there anyway to implement them ?
• Inter process communication in c++ (Process with multiple instance)

  I have a problem in which a single server is connected to a single client. However the number of instances of server and client can be more than one. As the port number is hardcoded in the code , what can be done such that multiple instances of process can run simultaneously. Any help would be really appreciated.
• How to write data from a linked list to a text file IN C++

  In C++, is there any way to write the data from each node of a linked list to a text file dynamically? Like when the program asks the user to enter the data in the program, it should go in a node of a linked list, while also going in the file.

  How do I achieve this using basic functions and header files? Not anything fancy or too complex, as I am a beginner.
• Processing a list thats extracted from a CSV file from a URL

  I'm trying to process data I've extracted from an online CSV file for a currency converter GUI application. CSV file link :(https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.zip).

  I've extracted the file and converted it from a string to a list using split(), what I'm trying to do next is to make a dictionary for each currency with the dates being the keys and the conversion rates being the values of the keys.

  Example of how I want the dictionary to be:

  USD: {
        (2018, 10, 8): 1.1478, 
        (2018, 10, 5): 1.1506, 
        (2018, 10, 4): 1.1502, 
        (2018, 10, 3): 1.1548, 
        (2018, 10, 2): 1.1543, 
        ...}
  

  I need to use this dictionary with the my PyQt5 widgets so I can perform the conversion and update the widgets.

  Libraries used in Application:

  import sys
  from PyQt5.QtWidgets import QLabel, QComboBox, QDoubleSpinBox, QCalendarWidget, QDialog, QApplication, QGridLayout
  from PyQt5 import QtCore
  from decimal import Decimal
  from urllib.request import urlretrieve
  import zipfile
  import pyqtgraph as pg
  

  The code i used to unzip the folder and convert it to a list:

  self.data = {} 
  url = 'https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.zip'  
  self.file, _ = urlretrieve(url)
  zip_file_object = zipfile.ZipFile(self.file, 'r')
  first_file = zip_file_object.namelist()[0]
  self.file = zip_file_object.open(first_file)
  content = self.file.read().decode()
  lst = []
  lst = content.split(",")
  

  Note: This was made using an Anaconda virtual enviroment
• I want to show Word documents in Python program output

  I have a few Word files which I want want to display in Python output. These Word files also contain multiple images. So how can I add them into the Python program for display?

  I tried:

  >>>from PIL import Image
  

  but that gives image in other software hence not satisfying my demand.