This example is an implementation of wc, a standard Unix program that counts characters, words, and lines in one or more files. The counts for each file given on the command line are printed, followed by a summary of totals for all files.
/*
* Copyright © 2006 Alistair Crooks. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// Small program to count words
totchars = totwords = totlines = 0;
void
pnums(int lines, int words, int chars, string f)
{
printf("\t%d\t%d\t%d\t%s\n", lines, words, chars, f);
}
// open file `f' and count chars, words and lines
void
wc(string f)
{
chars = words = lines = 0;
inword = 0;
if (f == "") {
fp = stdin;
} else {
// open the file and check it worked
fp = fopen(f, "r");
if (is_void(fp)) {
err = sprintf("%s isn't a valid file", f);
throw(err);
}
}
for (;;) {
s = fgets(fp);
if (is_void(s))
break;
for (i = 0 ; i < strlen(s) ; i++) {
chars += 1;
ch = substr(s, i, 1);
if (isspace(ch)) {
if (ch == '\n') {
lines += 1;
}
if (inword) {
inword = 0;
words += 1;
}
} else {
inword = 1;
}
}
}
if (f != "") {
fclose(fp);
}
// add file values onto global totals
totchars += chars;
totwords += words;
totlines += lines;
global("totchars", "totwords", "totlines");
// print file values
pnums(lines, words, chars, f);
}
if (argc < 2) {
wc("");
} else {
for (i = 1 ; i < argc ; i++) {
try {
wc(argv[i]);
} catch (e) {
print("Exception \x22", e, "\x22 occurred\n");
}
}
// print the totals
pnums(totlines, totwords, totchars, "totals");
}