1 files changed, 42 insertions, 0 deletions
diff --git a/ch2/2-03.c b/ch2/2-03.c
new file mode 100644
index 0000000..54ce89f
--- /dev/null
+++ b/ch2/2-03.c
@@ -0,0 +1,42 @@
+#include <stdio.h>
+
+
+unsigned int htoi(char hex[]) {
+    char c;
+    int i;
+    int length;
+    int power;
+    unsigned int result;
+
+    for (length = 0; hex[length] != '\0'; ++length)
+
+    power = 1;
+    result = 0;
+
+    for (i = length - 1; i >= 0; --i) {
+        c = hex[i];
+        printf("%c\n", c);
+
+        if (c >= 'a' && c <= 'f')
+            c = c - 'a' + 10;
+        else if (c >= 'A' && c <= 'F')
+            c = c - 'A' + 10;
+        else if (c >= '0' && c <= '9')
+            c = c - '0';
+        else if (c == 'x' || c == 'X')
+            break;
+        else
+            return 0;
+
+        result += c * power;
+        power *= 16;
+    }
+
+    return result;
+}
+
+
+int main() {
+    char hex[] = "0x589";
+    printf("%d\n", htoi(hex));
+}