我正在尝试在文件中写入特定数量的行，但我不断收到一个空行作为第一行

Question

i'm new here and i'm trying to solve a FILE problem in c. Basically i have to create a program that lets the user input how many lines he wants to write in a file, create a new file, write those lines and the reading it and establish how many lines where written and print the number of lines.

 int main() {
  int x, lc=0;
  char str[100];
  FILE *fp=fopen("test.txt","w");
  if (fp==NULL) {
    printf("\nOpening failed");
  }else{
    printf("\nOpened correctly");
  }
  printf("\nStrings to write:\n");
  scanf("%d",&x);
  for (int i = 0; i < x; i++) {
    fgets(str, sizeof str, stdin);
    fputs(str,fp);
  }
  fclose(fp);
  FILE *fr=fopen("test.txt", "r");
  while (fgets(str, 100, fr)!=NULL) {
      lc++;
    }
  fclose(fr);
  printf("\nThere are %d lines",lc);
  return 0;
 }

If i leave the code like this it messes up with my for cycle and it only lets me write 3 lines because it does put a free line at the start of the file. Can you explain how do i solve that? or if it's just how fgets and fputs behave and i have to remember that blank line at the start. Thank you in advance. (i'll leave a file output as follows with numbers for the lines)

1)
2)it seems to work
3)dhdhdh dhdh
4)random things 

Answer 1

As you can tell from the comments, there are a lot of ways to approach this task. The usage of "scanf" and "fgets" can get complex especially if mixed within the same reading task. But, just to give you one option as to deriving a solution, following is a snippet of code to offer one of many possible routes.

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

int main()
{
    int x, lc=0;
    char str[101];
    FILE *fp=fopen("test.txt","w");

    if (fp==NULL)
    {
        printf("Opening failed\n");
    }
    else
    {
        printf("Opened correctly\n");
    }

    printf("Strings to write: ");
    scanf("%d",&x);

    for (int i = 0; i < x; i++)
    {
        printf("Enter string: ");
        scanf("%s", str);
        fprintf(fp, "%s\n", str);
    }
    fclose(fp);

    FILE *fr=fopen("test.txt", "r");

    while (fgets(str, 100, fr)!=NULL)
    {
        lc++;
    }
    fclose(fr);

    printf("\nThere are %d lines\n",lc);

    return 0;
}

You will note that both "scanf" and "fgets" are being used in this example, but not in reference to the same file. For user input, "scanf" is getting used. Once the file is closed and then reopened for reading, "fgets" is being used for that portion of the task.

Testing this program snippet out resulted in matching up the same quantity of lines read from the file as were entered.

@Una:~/C_Programs/Console/FileWrite/bin/Release$ ./FileWrite 
Opened correctly
Strings to write: 4
Enter string: Welcome
Enter string: to
Enter string: Stack
Enter string: Overflow

There are 4 lines

Give it a try and see if it meets the spirit of your project.