now version controlled.

1 files changed, 42 insertions, 0 deletions

diff --git a/reverse.c b/reverse.c
new file mode 100644
index 0000000..a038df2
--- /dev/null
+++ b/reverse.c
@@ -0,0 +1,42 @@
+#include <u.h>
+#include <libc.h>
+
+char *
+reverse(char *s, int n)
+{
+	int i;
+	char tmp;
+
+	for(i = 0; i < n/2; i++){
+		tmp = s[i];
+		s[i] = s[n-i-1];
+		s[n-i-1] = tmp;
+	}
+	return s;
+}
+
+char *
+reversep(char *s, int n)
+{
+	char *bp, *ep;
+	char tmp;
+
+	for(bp = s, ep = s+n-1; bp != ep; bp++, ep--){
+		tmp = *bp;
+		*bp = *ep;
+		*ep = tmp;
+	}
+	return s;
+}
+
+void
+main()
+{
+	char s[] = "hello";
+
+	print("%s → ", s);
+	print("%s\n", reverse(s, strlen(s)));
+	print("%s → ", s);
+	print("%s\n", reversep(s, strlen(s)));
+	exits(0);
+}