CODEWITHSUNDEEP
cfilestdineof
collinskewl2
collinskewl2

Reputation: 67

C, how to stop stdin from outputting after each enter by the user?

I am new to C and I am encountering a problem with stdin I cannot find a solution to. My program either reads from file(s) or reads from stdin if no arguments (files) are provided by the user.

If the user doesn't supply any arguments then it will automatically read from stdin. My program is supposed to take in input (from file or stdin) and then remove the blank lines from it.

My problem arises when the program reads from stdin. Every time the user types something then presses enter the program automatically out puts the results. When I'd prefer enter to just be a newline.

How can I make it so the program waits for the user to hit EOF instead of each enter?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define NUMCHARS 1024

int main(int argc, char** argv){
  int good_file = 0;

  if (argc <= 1) {
    good_file++;
    test(stdin);
  }

  FILE* files[argc - 1];
  int i;
  for (i = 0; i < argc - 1; i++) {
    if ((files[i] = fopen(argv[i + 1], "r")) == NULL) {
      continue;
    } else {
      good_file++;
      test(files[i]);
    }
  }

  if (!good_file) {
    fprintf(stderr, "ERROR!\n");
  }
}

int test(FILE *file) {
  char buffer[NUMCHARS];

  while (fgets(buffer, NUMCHARS, file) != NULL)
    part2(buffer);
  fclose(file);
}

int part2(char *buffer) {
  if (!is_all_white(buffer)) {
    fputs(buffer, stdout);
  }
}

int is_all_white(char *s) {
  while (*s) {
    if (!('\n' == *s || '\t' == *s || ' ' == *s))
      return 0;
    s += 1;
  }
  return 1;
}

I appreciate any feedback!

Upvotes: 2

Views: 410

Answers (2)

phil
phil

Reputation: 565

Pre process stdin into a temp work file, this will then give you the control you require. Use function mkstemp.

Be warned stdin is a pipe, where as the fopen files are probably disk files

Upvotes: -1

Politank-Z
Politank-Z

Reputation: 3719

It isn't an issue with stdin per se - if you want to wait to output your data, you will have to store it. You could write it to a file and read it back afterward. You could use malloc and realloc to store the data in memory. Mainly, if you don't want the data to output on every line, you need not to output it on every line.

Upvotes: 3

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