java中的求和函数
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summation function in java
提问by tawheed
I am getting strange behavior with this basic piece of java code
我对这段基本的 Java 代码产生了奇怪的行为
public class Sigma {
public static void main(String[] args) {
int sum = sigma(3);
System.out.println(sum);
}
public static int sigma(int n){
int sum = 0;
for (int i = 0; i <= n; i++) {
sum += 1;
}
return sum;
}
}
The expected output is 6, however when I run the code I get 4
预期的输出是6，但是当我运行代码时，我得到4
采纳答案by Algorithmist
This is wrong, you should change sum += 1;to sum += i;
这是错误的，您应该更改sum += 1;为 sum += i;
And if you are doing an AP summation from 1 to N better use directly the formula:
如果你正在做从 1 到 N 的 AP 求和，最好直接使用公式：
(n*(n+1))/2
(n*(n+1))/2
回答by ihsan kocak
You should change the code as sum+=1to sum+=i;
你应该将代码修改sum+=1，以sum+=i;
