Java 带数组的点积
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Dot product with arrays
提问by Sophia Ali
In class we had to write a small code using Dot Product to find the sum of two arrays(array a and array b). I have written my code however when I run it it does not give me the answer. My professor said my loop was wrong however I do not think it is. Is the part that says i<a.lengthnot allowed in a for loop parameter? Because even if I set it to n it still does not give me the sum.
在课堂上，我们必须使用 Dot Product 编写一个小代码来查找两个数组（数组 a 和数组 b）的总和。我已经编写了我的代码，但是当我运行它时，它并没有给我答案。我的教授说我的循环错了，但我认为不是。i<a.length在 for 循环参数中表示不允许的部分？因为即使我将它设置为 n 它仍然不会给我总和。
Here is my code:
这是我的代码：
public class arrayExample {
public static void main (String [] args) {
int[] a = {1,2,2,1};
int[] b = {1,2,2,1};
int n = a.length;
int sum = 0;
for (int i = 0; i < a.length; i++) {
sum += a[n] * b[n];
}
System.out.println(sum);
}
}
采纳答案by arshajii
nisn't the loop control variable, it's a.lengthwhich is an out of bounds index. You probably meant
n不是循环控制变量，它a.length是越界索引。你可能是说
sum += a[i] * b[i];
And, although it does not matter directly, you probablymeant your for-loop to be
而且，虽然这并不重要，但您可能意味着您的for-loop 是
for (int i = 0; i < n; i++)
(I would assume that's the reason you have nin the first place.)
（我认为这就是您n首先拥有的原因。）
回答by Mansi Edi
public class arrayExample
{
public static void main (String [] args)
{
int[] a = {1,2,2,1};
int[] b = {1,2,2,1};
int n = a.length;
int sum = 0;
for (int i = 0; i < n; i++)
{
sum += a[i] * b[i];
}
System.out.println(sum);
}
}
