diff --git a/untletter/src/main/java/com/swpu/letter.java b/untletter/src/main/java/com/swpu/letter.java
new file mode 100644
index 0000000000000000000000000000000000000000..0a8ab91b1aa82674ae1e76a6dea310ce6605200b
--- /dev/null
+++ b/untletter/src/main/java/com/swpu/letter.java
@@ -0,0 +1,30 @@
+package com.swpu;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class letter {
+    public static void main(String[] args) {
+        List<String> food = new ArrayList();
+        var food1 = new ArrayList<String>();
+        Map<String, String> price = new HashMap();
+        var price2 = new HashMap<String, String>();
+        food.add("西红柿");
+        food.add("鸡蛋");
+        food1.add("猪");
+        food1.add("青椒");
+        System.out.println(food);
+        System.out.println(food1);
+
+
+        for (var i = 0; i < food.size(); i++) {
+            System.out.println("第" + i + "是：" + food.get(i));
+            var data = food.get(i);
+            price.put(data, i * 2 + "$$$");
+        }
+        System.out.println("map:" + price);
+
+    }
+}
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