I am new to C programming and I am confused how to skip the first two lines in a file. I tried using fgets and fscanf, but I can't figured it out how to do it. Assume I have a file txt like this:

1 Username: Test
2 Password: 12345
3
4

So how can I start scan from line 3 and skip lines 1 and 2? Thank you.

CodePudding user response：

There are multiple ways to skip a line from a standard stream:

• you can read a line with fgets() into a char array and ignore it. This will effectively consume the line if the array if long enough.

• you can use fscanf() with cryptic conversion specifications:

    fscanf(fp, "%*[^\n]");   // consume bytes different from newline, if any
    fscanf(fp, "%*1[\n]");   // consume a single newline, if present
  

• you can read and discard bytes with a simple loop:

    int c;
    while ((c = getc(fp)) != EOF && c != '\n')
        continue;
  

To skip 2 lines, repeat the above code twice or better write a function int skip_line(FILE *fp) with the third option, returning c and call it twice.

#include <stdio.h>

// read and discard a line from stream fp, return EOF at end of file.
int skip_line(FILE *fp) {
    int c;
    while ((c = getc(fp)) != EOF && c != '\n')
        continue;
    return c;
}

CodePudding user response：

You can use the following code to skip two lines :

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