diff --git a/x_ctypes/src/x_ctypes.c b/x_ctypes/src/x_ctypes.c
new file mode 100644
index 0000000..f49da04
--- /dev/null
+++ b/x_ctypes/src/x_ctypes.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int x_isdigit(const char x){
+	if ( x > 48 && x < 57 ){
+		return 1;
+	}
+	else if ( x > 0 && x < 9 ){
+		return 1;
+	}
+
+	return 0;
+}
+
diff --git a/x_ctypes/src/x_ctypes.h b/x_ctypes/src/x_ctypes.h
new file mode 100644
index 0000000..3d08dab
--- /dev/null
+++ b/x_ctypes/src/x_ctypes.h
@@ -0,0 +1,8 @@
+#ifndef X_CTYPES_H
+#define X_CTYPES_H
+
+
+// returns 0 if x is not a digit and 1 if it is
+int x_isdigit(char x);
+
+#endif