Initial commit

1 files changed, 49 insertions, 0 deletions

diff --git a/two/conv.c b/two/conv.c
new file mode 100644
index 0000000..7bf218a
--- /dev/null
+++ b/two/conv.c
@@ -0,0 +1,49 @@
+#include <stdio.h>
+
+int
+lower(int c)
+{
+	if (c >= 'A' && c <= 'Z') {
+		return c + 'a' - 'A';
+	} else {
+		return c;
+	}
+}
+
+int
+atoi(char s[])
+{
+	int i, n;
+
+	n = 0;
+	for (i = 0; s[i] >= '0' && s[i] <= '9'; ++i) {
+		n = 10 * n + (s[i] - '0');
+	}
+	return n;
+}
+
+/* convert string of hex digits into int digits */
+int
+htoi(char s[])
+{
+	int i, n;
+
+	n = 0;
+	for (i = 0; s[i] >= '0' && s[i] <= 'f'; ++i) {
+		if (s[i] >= '0' && s[i] <= '9') {
+			n = 16 * n + (s[i] - '0');
+		} else if (s[i] >= 'A' && s[i] <= 'F') {
+			n = 16 * n + (s[i] - 'A' + 10);
+		} else if (s[i] >= 'a' && s[i] <= 'f') {
+			n = 16 * n + (s[i] - 'a' + 10);
+		}
+	}
+	return n;
+}
+
+int
+main()
+{
+	printf("%d\n", htoi("1f"));
+	return 0;
+}