How to get string terminated with new line in file handling using fscanf-CodePudding

I have these in my file:

JOS BUTTLER
JASON ROY
DAWID MALAN
JONNY BAISTROW
BEN STOKES

in different lines. And I want them to extract in my program to print them on the exact way they are in file. My imaginary output screen is:

JOS BUTTLER
JASON ROY
DAWID MALAN
JONNY BAISTROW
BEN STOKES

How would I do it using fscanf() and printf(). Moreover suggest me the way to change the delimiters of fscanf() to \n I have tried something like this:

char n[5][30];
    printf("Name of 5 cricketers read from the file:\n");
   for(i=0;i<5;i  )
   { 
            fscanf(fp,"%[^\n]s",&n[i]);
            printf("%s ",n[i]);         
    }
    fclose(fp);
}

But it works only for the first string and other string could not be displayed. There were garbage values.

CodePudding user response：

Be protected from buffer overflows limiting the length of the input, use ")[^\n]" instead of "%[^\n]s" (you don't need the s specifier)

Consume the trailing new line (your wildcard ^\n reads until a new line is found) using %*c, * means that a char will be read but won't be assigned:

fscanf(fp, ")[^\n]%*c", n[i]);

or better yet (as pointed out by @WeatherVane), add a space before %, this will consume any blank space including tabs, spaces and new lines that may be left in the buffer from the previous read:

fscanf(fp, " )[^\n]", n[i]);

Notice that you don't need an ampersand in &n[i], fscanf wants a pointer but n[i] is already (decays into) a pointer when passed as an argument.

Finally, as pointed out by @paddy, fgets does all that for you and is a safer function, always prefer fgets.

CodePudding user response：

How to get string terminated with new line in file handling using fscanf

Use fgets() to read a line of input into a string. It also reads and saves the line's '\n'.

Buffer size 30 may be too small, consider 60.

To detect if the line is too long and lop off the '\n', read in at least 2 characters.

// char n[5][30];
#define NAME_N 5
#define NAME_SIZE 30
char n[NAME_N][NAME_SIZE]

char buf[NAME_SIZE   2]
while (i < NAME_N && fgets(buf, sizeof buf, fp) != NULL) {
  size_t len = strlen(buf);

  // Lop off potential trailing '\n'
  if (len > 0 && buf[len - 1] == '\n') {
    buf[--len] = '\0';
  }

  // Handle unusual name length
  if (len >= NAME_SIZE || len == 0) {
    fprintf(stderr, "Unacceptable name <%s>.\n", buf);
    exit(EXIT_FAILURE);
  }

  // Success
  strcpy(n[i], buf);
  printf("%s\n", n[i]); 
  i  ;
}