now version controlled.

1 files changed, 60 insertions, 0 deletions

diff --git a/printdec.c b/printdec.c
new file mode 100644
index 0000000..c061c22
--- /dev/null
+++ b/printdec.c
@@ -0,0 +1,60 @@
+#include <u.h>
+#include <libc.h>
+
+void
+swap(char *a, char *b)
+{
+	char tmp;
+
+	tmp = *a;
+	*a = *b;
+	*b = tmp;
+}
+
+void
+srev(char *s, char *e)
+{
+	while(s < e)
+		swap(s++, e--);
+}
+
+void
+printdec(int n)
+{
+	char buf[16];
+	char *p, *e;
+	int r;
+
+	p = buf;
+	e = buf+sizeof(buf)-1;
+	while(n > 0 && p < e){
+		r = n%10;
+		*p++ = '0'+r;
+		n /= 10;
+	}
+	*p = 0;
+	print("%s\n", buf);
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: %s number\n", argv0);
+	exits("usage");
+}
+
+void
+main(int argc, char *argv[])
+{
+	int n;
+
+	ARGBEGIN{
+	default: usage();
+	}ARGEND
+	if(argc != 1)
+		usage();
+	srev(argv[0], argv[0]+strlen(argv[0])-1);
+	n = strtol(argv[0], nil, 10);
+	printdec(n);
+	exits(0);
+}