start:java8

com/study/demo/test1_3.java

@@ -0,0 +1,19 @@
+package com.study.demo;
+
+public class test3_1_99 {
+    public static void main(String[] args) {
+        int[] numbers = new int[99];
+
+        for (int i = 0; i < numbers.length; i++) {
+            numbers[i] = i + 1;
+        }
+
+        int sum = 0;
+        for (int i = 0; i < numbers.length; i++) {
+            sum += numbers[i];
+        }
+
+        System.out.println("1+2+...+99 的和 = " + sum);
+    }
+}
+