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package com.zyx.cn.baidu_test.day1; /** 1.S=1+ 2 +3…＋99 2.S＝1 +1/2+ 1/3 …+1/99 3.S＝1－3＋5－7＋…－99 4.S＝1－1/3+ 1/5－7 …－1/99 * @author yltd * */ public class AccFor { public static void main(String[] args) { one(99);//4950 two(99);//1.0 three(99);//50 four(99);//1 } //求和 public static int one(int number){ int sum = 0; for (int i = 1; i <= number; i++) { sum+=i; } System.out.println(sum); return sum; } //分数求和 public static Double two(int number){ Double sum =0d; for (int i = 1; i <= number; i++) { Double d =(double) (1/i); sum+=d; } System.out.println(sum); return sum; } public static int three(int number){ int sum =0; int count =1; for (int i = 1; i <=number; i++) { if(i%2 !=0 && count%2!=0){ sum+=i; } if(count%2==0){ sum-=i; } count++; } System.out.println(sum + "----"+count); return sum; } public static int four(int number){ int sum =0; int count =1; for (int i = 1; i <=number; i++) { if(i%2 !=0 && count%2!=0){ sum += 1/i; } if(count%2==0){ sum -= 1/i; } count++; } System.out.println(sum + "----"+count); return sum; } }
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