Java/com/study/demo/test1_3.java

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);
  }
}