两个向量的总和.. !! [英] Sum Of Two Vectors ..!!

问题描述

我正在尝试编写代码，即两个向量的和.我全力以赴，失败了，
你能帮我吗..?！ (重新更新)

I''m trying to write a code i.e sum of two vectors. I''ve put my all efforts and fail,
Will You Please Help Me .. ?! (RE-UPDATED)

#include "stdafx.h"
#include "stdafx.h"
#include <iostream>

using namespace::std;

int SumOfColumns (int p[], int q[], int z[])
{

    int i=0;

    for(i=0; i<=4; i++)
    {
        z[i]=p[i] + q[i];
    }
    return 0;
}

void main()
{
    int p[4]={9,1,5,4};
    int q[4]={3,1,2,2};
    int z[4]={0,0,0,0};
    cout<<SumOfColumns(p[], q[], z[])<< endl;
    //cout<<z[0];
    //cout<<z[1];
    //cout[2];
    //cout<<z[3]<<endl;

推荐答案

让我们看看.

您具有接受三个向量并只返回一个整数的函数SumOfColumns，但是当您调用该函数时，您只是给出(4,4,4)，而这些都是纯整数，根本不是向量.
在第二学期，您不会在任何地方声明z[].您应该在使用它之前声明它.
然后，您要制作一个遍历数组的双循环，如果要添加像p[4][4]这样的向量，则将需要一个双遍循环，但是您的向量只是一维，所以这是错误的.
然后，您声明sum并在z[sum]=...中使用它，这是错误的，因为z[]将具有4个元素，就像其他两个元素一样.您只需要使用与读取p[]和q[]的值相同的位置，所以将sum用作位置会给您带来问题，因为您正尝试访问一个不存在的位置. br/> 另一个问题是，您要返回302作为函数的返回值，因此cout的输出将仅为302，而无需注意z[]的值.如果要打印总和，则需要在此处使用z[].

另外，请访问 http://www.cplusplus.com/doc/tutorial/arrays/ [^ ]

对我来说，向您发布执行该操作的代码本来会更容易，但是那样一来，您仅复制解决方案就不会学到任何东西.请阅读我的评论，然后尝试更正您的代码.如果您更改代码后仍然遇到问题，请使用改进问题"来更改您的信息并提供新代码.然后使用有问题或评论?"说我你改变了它.我会检查的.


问题发布后的新内容
好吧，让我们看看.
现在，添加p[]和q[]到几乎是正确的:您已经将z声明为int*，但是p和q不是int* .由于您已经开始，所以我建议您一步一步地进行操作(换句话说，将指针留给以后使用).您可以使用与p和q相同的方式声明z，但是将0作为所有4个组件的初始值. 然后，您仍然会返回302作为该函数的返回值，并直接在cout处调用该函数，因此您不会在任何地方看到z[]的内容.您可以通过许多不同的方式解决此问题:
--- a)您将SumOfColumns声明为void，不返回任何return.然后，在将数组声明为独立行之后调用函数，然后手动进行cout传递z[]的组成部分(这意味着4次，对于z []的每个组成部分一次)
--- b)将cout的行写在循环内(添加组件时)，而忘记了main中的那一行.
--- c)创建一个函数来打印z []的内容，并在调用SumOfColumns之后调用它(请看一下我第一次给您的链接说明的末尾，他们有一个例子在那里，数组作为参数"部分)
---(其他可能性)

告诉我你什么时候完成

最后评论后的新内容
如果您仔细阅读并分析所做的更改，那么您已经拥有获取解决方案所需的所有信息.在函数中返回302之前:没有出现现在的错误，但是在cout中打印302(=函数的返回值).
-如果不要求在与cout相同的行中调用该函数，则只需要在声明数组之后调用该函数，然后像在c中所做的那样打印z[i]的值您的最新版本.
-但是，如果您必须在与cout相同的行中调用该函数，则可以按以下步骤进行操作.不必在函数内部进行循环以仅通过调用一次添加所有4个组件，而必须在main中进行循环，并仅提供p[]和q[]的实际组件作为参数，然后return值的加法.为此，您需要声明该函数以返回一个int并接受两个int作为参数(而不是整个数组).

再试一次，告诉我什么时候完成

Let''s see.

You have the function SumOfColumns that accept three vectors and give back just an int, but when you call the function you are just giving (4,4,4) and those are plain integers, not vectors at all.
On second term, you are not declaring z[] anywhere. You should declare it before using it.
Then you are making a double loop to go through the arrays, a double loop would be needed if you are adding vectors like p[4][4] but yours are just one dimension, so that''s wrong.
Then you are declaring sum and using it in z[sum]=..., that is false because z[] is going to have 4 elements just as the other two. You just need to use the same position that you are using to read the values of p[] and q[], so using sum as position will give you problems, because you are trying to access to a non existant position.
Other issue is, you are giving 302 back as return value of the function, so the output of cout will be just 302, without paying atention to the values of z[]. If you want to print out the sum, you will need to use z[] there.

As addition, have a look to http://www.cplusplus.com/doc/tutorial/arrays/[^]

It would have been easier for me to post you the code to do it, but then you won''t have learn anything just copying the solution. Please read my comments and try to correct your code. If you change your code and still gives you problems, then please use "improve question" to change your message and give the new code. Then use "have a question or comment?" to say me that you changed it. I will check it.


New content after the edition of the question
Ok, let''s see.
The addition of p[] and q[] to give z[] is now almost correct: You have declared z as int* but p and q are not int*. Since you are starting I recommend you go one step after another (in other words, leave pointers for later). You can declare z the same way you did with p and q, but giving 0 as initial value for all 4 components.
Then you are still giving back 302 as return value of the function, and calling the function directly at cout, so you are not going to see the content of z[] anywhere. You can solve this in many different ways:
--- a) You declare SumOfColumns as void, giving no return back. Then you call the function after the declaration of the arrays as stand alone line, and then you do cout passing the components of z[] manually (it means 4 times, one for each component of z[])
--- b) You write the line of the cout inside the loop (when you are adding the components) and forget about the one in main.
--- c) You create a function to print the content of z[] and you call it after the call of SumOfColumns (take a look at the end of the explanation of the link I gave you the first time, they have an example there, Section "array as parameter")
--- (other possibilities)

Tell me when you are done

New content after last comments
If you read carefully and analyze the changes you have done, you already have all the information you need to get the solution. Before you were returning 302 in your function: You didn''t got the error you have now but you were printing 302 in the cout (= the return value of the function).
- If it is not a requirement that you call the function in the same line as cout, then you just have to call the function after the declaration of the arrays alone, and then print values of z[i] as you have done in your last version.
- But... if you have to call the function in the same line as cout... you can do it as follows. Instead of making the loop inside the function to add all 4 components with just one call of the function, you have to make the loop in main and give only the actual component of p[] and q[] as parameter, and then return the addition of the values. In order to do that you need to declare the function to give an int back and to accept two ints as parameter (not the full arrays).

Try it another time and tell me when you are done

尝试一下

Try this

#include "stdafx.h"
#include <iostream>
 
using namespace::std;
 
void SumOfColumns (int *p, int *q, int *z)
{
    for(int i = 0; i < 4; i++)
    {
        z[i] = p[i] + q[i];
    }
}
 
void main()
{
    int p[4]={9, 1, 5, 4};
    int q[4]={3, 1, 2, 2};
    int *z = new int[4];
    SumOfColumns(p, q, z);
    for (int i = 0; i < 4; ++i)
    {
	cout << i << ": " << z[i] << endl;
    }
}

我会写

void SumOfColumns (int p[], int q[], int z[], size_t size)
{
    int i;
    for(i=0; i<size; i++)
    {
        z[i] = p[i] + q[i];
    }
}

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