Cramming data into a single statement

Take the following word-count program I have, where a word is (naively) taken as alnums between whitespace:

#include<stdio.h>
#include<ctype.h>
#include<stdbool.h>

int main(void)
{
    // grab a segment of text until EOF
    int current_char;
    int num_words=0, num_chars=0, num_lines=0; // ignore whitespace
    bool in_word;

    printf("Enter your text here:\n");

    while ((current_char=getchar()) != EOF)
    {
        if (current_char == '\n')
            in_word ? num_words++, num_lines ++, in_word-- : num_lines++;
        else if (isalnum(current_char))
            num_chars ++, in_word=true;
        else if (isspace(current_char))
            in_word ? num_words++, in_word-- : ' ';
    }
    if (in_word) num_words ++;

    printf("\nChar Count: %d | Line count: %d | Word count: %d\n", num_chars, num_lines, num_words);

}

Ignoring the naivety of the word-detection, is this considered bad practice to cram things into a single statement so braces can be skipped? For example, I suppose the 'long-form' version of the first if would be:

if (current_char == '\n')
{
    num_lines ++;
    if (in_word)
        num_words ++;
    in_word = false;
}

This seems more readable and easy for me to understand, but often I'll see long one-liners in C and so I was wondering why one choice may be used over the other.

For example, here's a line from postgres which seems to be like a too-long-one-liner that I have a difficult time understanding:

if (!gsets)
    ereport(ERROR,
        (errcode(ERRCODE_STATEMENT_TOO_COMPLEX),
        errmsg("too many grouping sets present (maximum 4096)"),
        parser_errposition(pstate,
            qry->groupClause
            ? exprLocation((Node *) qry->groupClause)
            : exprLocation((Node *) qry->groupingSets))));