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authorzlg <zlg@zlg.space>2013-09-26 07:17:51 -0500
committerzlg <zlg@zlg.space>2013-09-26 07:17:51 -0500
commit22ddf92e89b19c30ff77b368cab60cc95315db35 (patch)
tree5085347805262c7e35b8ce5393fd8b4787f7285a /ch5
parentClean up 5-10's printf() calls (diff)
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Solve Exercise 5-11: `entab` and `detab` remixed!
This one was pretty rough. At first I wanted to include a bunch of error-catching and "smart" stuff. When I took a second look at it and realized `itoa` returns 0 on a string, things became a bit easier. I may have been able to outsource a few things to a function or two, but overall I think it worked out.
Diffstat (limited to 'ch5')
-rw-r--r--ch5/5-11_detab-remixed.c61
-rw-r--r--ch5/5-11_entab-remixed.c76
2 files changed, 137 insertions, 0 deletions
diff --git a/ch5/5-11_detab-remixed.c b/ch5/5-11_detab-remixed.c
new file mode 100644
index 0000000..43bffb4
--- /dev/null
+++ b/ch5/5-11_detab-remixed.c
@@ -0,0 +1,61 @@
+#include <stdio.h>
+
+/* The C Programming Language: 2nd Edition
+ *
+ * Exercise 5-11: Modify the programs entab and detab (written as exercises in
+ * Chapter 1) to accept a list of tab stops as arguments. Use the default tab
+ * settings if there are no arguments.
+ */
+
+#define TABWIDTH 8
+
+int main(int argc, char *argv[]) {
+ int column, c, tabnum, stop;
+ column = 0;
+
+ if (argc > 1) {
+ tabnum = 1;
+ stop = atoi(argv[tabnum]);
+ } else {
+ tabnum = 0;
+ }
+
+ while ((c = getchar()) != EOF) {
+ if (c == '\t') {
+ if (argc > 1) {
+ // advance the argument if we're ahead of the last one
+ if (column > stop && tabnum < (argc -1)) {
+ stop = atoi(argv[++tabnum]);
+ }
+ // insert our spaces up to the tabstop
+ while (column <= stop) {
+ putchar(' ');
+ column++;
+ }
+ // advance the argument (again) if needed.
+ if (tabnum < (argc - 1)) {
+ stop = atoi(argv[++tabnum]);
+ }
+ } else {
+ // default tabstopping
+ while (column % TABWIDTH != 1) {
+ putchar(' ');
+ column++;
+ }
+ }
+ } else {
+ // reset counters and the arglist
+ if (c == '\n') {
+ column = 0;
+ if (tabnum > 0) {
+ tabnum = 1;
+ stop = atoi(argv[tabnum]);
+ }
+ }
+ putchar(c);
+ column++;
+ }
+ }
+
+ return 0;
+}
diff --git a/ch5/5-11_entab-remixed.c b/ch5/5-11_entab-remixed.c
new file mode 100644
index 0000000..8f6f7d4
--- /dev/null
+++ b/ch5/5-11_entab-remixed.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/* The C Programming Language: 2nd Edition
+ *
+ * Exercise 5-11: Modify the programs entab and detab (written as exercises in
+ * Chapter 1) to accept a list of tab stops as arguments. Use the default tab
+ * settings if there are no arguments.
+ */
+
+/* The directions for this exercise aren't terribly clear. The way I see it,
+ * each argument is a character column that all tabs should align to. For the
+ * entab portion, I should count 2+ spaces forward and, if I reach a tabstop,
+ * insert a tab. Then move onto the next argument. If 2+ spaces are present,
+ * but don't reach the tabstop threshold, the spaces are left alone. This is
+ * the best I could manage with the ambiguous instructions.
+ */
+
+#define TABWIDTH 8
+
+int main(int argc, char *argv[]) {
+ int column, c, spaces, tabnum, stop;
+ spaces = column = 0;
+
+ if (argc > 1) {
+ tabnum = 1;
+ stop = atoi(argv[tabnum]);
+ } else {
+ tabnum = 0;
+ }
+
+ while ((c = getchar()) != EOF) {
+ column++;
+
+ if (c == ' ') {
+ spaces++;
+ if (argc > 1) {
+ if (column == stop) {
+ if (tabnum < (argc - 1)) {
+ stop = atoi(argv[++tabnum]);
+ }
+ if (spaces > 1) {
+ putchar('\t');
+ spaces = 0;
+ }
+ } else if (column > stop && tabnum < (argc -1)) {
+ stop = atoi(argv[++tabnum]);
+ }
+ } else {
+ // we need to do default tabstopping
+ if (column % TABWIDTH == 0 && spaces > 1) {
+ putchar('\t');
+ spaces = 0;
+ }
+ }
+ } else {
+ // output all extra spaces first
+ while (spaces > 0) {
+ putchar(' ');
+ spaces--;
+ }
+ // reset the counts and argument position on a newline
+ if (c == '\n') {
+ column = 0;
+ spaces = 0;
+ if (tabnum > 0) {
+ tabnum = 1;
+ stop = atoi(argv[tabnum]);
+ }
+ }
+ putchar(c);
+ }
+ }
+
+ return 0;
+}