Wie wird zeilenweise aus einer Datei gelesen?

Question

#define MAX_READING 100; 

char str_orders[MAX_READING], str_books[MAX_READING], 
    books_updated[MAX_READING], *token, *token1, p[MAX_READING], 
    File * books_orders, *books, books_updated; 

while (fgets (str_orders, MAX_READING, books_orders) != NULL) { 
    if (str_orders[strlen (str_orders) - 1] == '\n') 
     str_orders[(strlen (str_orders) - 1)] = 0; 
    if (strcmp (str_orders, "Initialize") == 0) { 
     while (fgets (str_books, MAX_READING, books) != NULL) { 
      if (str_books[strlen (str_books) - 1] == '\n') 
       str_books[(strlen (str_books) - 1)] = 0; 
      token = strtok (str_books, "$$$"); 
      strcpy (p, token); 
      token = strtok (NULL, "$$$"); 
      copy = atoi (token); 
      add (head, p, copy); 
     } 
    } 
    printf ("%s\n", str_orders); 
    if (strcmp (str_orders, "Initialize") != 0 
     && strcmp (str_orders, "Finalize") != 0) { 
     token1 = strtok (str_orders, "$$$"); 
     strcpy (order, token1); 
     token1 = strtok (NULL, "$$$"); 
     strcpy (book_name, token1); 
     token1 = strtok (NULL, "$$$"); 
     copy = atoi (token1); 
     if (strcmp (order, "Return") == 0) 
      returnbook (head, book_name, copy); 
     if (strcmp (order, "Borrow") == 0) 
      borrowbook (head, book_name, copy); 
     if (strcmp (str_orders, "Finalize") == 0) { 
      while (head != NULL) { 
       fprintf (books_update, "%s", head->name); 
       fprintf (books_update, " $$$ "); 
       fprintf (books_update, "%d", head->copies); 
      } 
     } 
    } 

Ich versuche, Zeile für Zeile aus einer txt-Datei zu lesen in C. ich die fgets Funktion verwendet, um sie zu lesen, aber die Funktion liest die erste Zeile „Intalize“ genannt, gehen keine anderen Linien in der Datei. Ich habe versucht,

printf("%s",str_orders) 

und es gibt "Intalize" zurück. Die fgets ging nicht zu den Zeilen.

Wie kann ich das beheben?

Answer 1

So würde ich gehen, um eine Datei Zeile für Zeile zu lesen.

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 

// Read a line from the file and put it into the buffer, and return 1 if we're at the end of the file 
int readLine(FILE *file, char *buffer, int bufferLength) { 
    int bufferPosition = 0; 

    while (true) { 
     // Copy the character into the buffer 
     buffer[bufferPosition] = fgetc(file); 

     if (feof(file)) { 
      // Return 1 if we're at the end of the file 
      buffer[bufferPosition] = 0; 
      return 1; 
     } else if (buffer[bufferPosition] == '\n') { 
      // Return if we're at the end of a line 
      buffer[bufferPosition] = 0; 
      return 0; 
     } else { 
      // Go to the next character 
      bufferPosition++; 
      if (bufferPosition == bufferLength) { 
       // If we fill up the buffer, exit here 
       buffer[bufferPosition - 1] = 0; 
       break; 
      } 
     } 
    } 

    return 0; 
} 

int main(int argc, char **argv) { 
    FILE *file = fopen("file.txt", "rb"); 

    int lineNumber = 1; 
    char line[4096]; 
    while (true) { 
     int read = readLine(file, line, sizeof(line)); 
     printf("Line %d: %s\n", lineNumber++, line); 
     if (read) break; // The end of the file 
    } 

    fclose(file); 
    return 0; 
}