--- /dev/null
+const int TrigPin = 2; // 2
+const int EchoPin = 3; // ~3
+
+float dist;
+
+void setup()
+{
+ Serial.begin(9600);
+ pinMode(TrigPin, OUTPUT);
+ pinMode(EchoPin, INPUT);
+ Serial.println("Ultrasonic Sensor:");
+}
+
+void loop()
+{
+ digitalWrite(TrigPin, LOW);
+ delayMicroseconds(2);
+ digitalWrite(TrigPin, HIGH);
+ delayMicroseconds(10);
+ digitalWrite(TrigPin, LOW);
+
+ dist = pulseIn(EchoPin, HIGH) / 58.0;
+
+ Serial.print(dist);
+ Serial.println("cm");
+ delay(100);
+}
--- /dev/null
+/*
+ * ------------------------------------------------------------------------
+ * File Name: htn.c
+ * Author: Zhao Yanbai
+ * Sat Jul 12 17:00:31 2014
+ * Description: none
+ * ------------------------------------------------------------------------
+ */
+#include<stdio.h>
+
+int main(int argc, char *argv[]){
+ unsigned int ch;
+ while(scanf("%x",&ch) != EOF)
+ printf("%u\n",ch);
+
+ return 0;
+}
--- /dev/null
+/*
+ * ------------------------------------------------------------------------
+ * File Name: nth.cc
+ * Author: Zhao Yanbai
+ * Sat Jul 12 16:20:37 2014
+ * Description: none
+ * ------------------------------------------------------------------------
+ */
+#include<iostream>
+#include<cstdio>
+using namespace std;
+
+int main(int argc, char *argv[]) {
+
+ unsigned int n;
+
+ while(cin >> n)
+ {
+ printf("%08x\n", n);
+ }
+
+ return 0;
+}