程序员面试一百题-08-求1+2+...+n-Java实现

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package org.yzs.test;

/**
 * @description: 利用Java的构造函数求1+2+...+n
 * @create: 2018-12-14 11:53:43
 */
public class Sum {
    private static int globalN;
    private static int sum;

    //构造函数
    Sum() {
        globalN++;
        sum += globalN;
        System.out.println("Constructor has been called " + globalN + " times.");
    }

    //重置函数
    static void reset() {
        globalN = 0;
        sum = 0;
    }

    //获取和
    static int getSum() {
        return sum;
    }

    public static void main(String[] args) {
        reset();
        int localN = 10;
        //此时只是声明了数组arr
        Sum[] arr = new Sum[localN];
        //Java类数组的创建与调用和C++是不同的
        for (int i = 0; i < localN; i++) {
            //为每一个数组变量赋值
            arr[i] = new Sum();
        }
        System.out.println("Sum is " + getSum() + ".");
    }
}