错误的指向数组的函数返回一个指针 [英] Error in returning a pointer from a function that points to an array

问题描述

我是有点在小提琴，我不知道为什么我的code带来了编译时出现以下错误：

I'm in a bit of a fiddle in that I don't know why my code brings up the following error when compiling:

1>..\SA.cpp(81) : error C2664: 'CFE' : cannot convert parameter 1 from 'int' to 'int []'
1>        Conversion from integral type to pointer type requires reinterpret_cast, C-style cast or function-style cast

从本质上讲，我想：

Essentially I am trying to:

第一步：从使用向量转换为一个数组：

Step1: Convert from a vector to an array using:

int* VecToArray(vector<int> Vec)
{
    int ary[Vec.size()];

    for(int i = 0; i < Vec.size(); i++)
        ary[i] = Vec[i];

    return ary;
}

第二步：在调用一个函数到其中的阵列是paremeter，它从一个新生成的数组返回一个指针：

Step2: Calling upon a function into which the array is an paremeter and it returns a pointer from a newly generated array:

int* CFE(int density[])
{
   ...do stuff to generate 'double Energy[]'....

    return Energy;
}

步骤3：在第三函数使用该指针calcualte能量的总和[]：

Step 3: Using this pointer in a third function to calcualte the sum of Energy[]:

double ObjFunction (double *E_Array) 
{
    double SumEnergy = 0;

    int n = 10; // Is irrelivant

    for (int i = 0; i < n; i++)
    {
        SumEnergy += E_Array[i];
    }

    return SumEnergy;
}

要做出简单的编码我用的功能，像这样，在VectorName是一个整数向量：

To make for simpler coding I've used the functions like so, where VectorName is an integer vector:

double TotalEnergy = ObjFunction ( CFE ( VecToArray ( VectorName ) ) );

我明明收到的参数类型不对的地方，但我只是不能明白为什么自己。任何人都可以用一个更有经验的眼睛在发现它/它们帮助？

I am obviously getting the parameter types wrong somewhere, though I just cant see why myself. Could anyone with a more experienced eye assist in spotting it/them?

推荐答案

哪里能源从何而来？如果它是一个双[] ，那么你不能只是将其转换为为int * 。

Where does Energy come from? If it's a double[] then you can't just cast it to an int*.

的std ::矢量＆lt; INT＆GT; 保证是连续的，所以如果你想转换一个的std ::矢量＆lt; INT＆GT; VectorName 到 const int的* 使用＆放大器; VectorName [0] 。如果，另一方面，您的CFE函数修改数组传递，它可能会更好过本地创建它。

std::vector<int> is guaranteed to be contiguous, so if you want to convert a std::vector<int> VectorName to an const int* use &VectorName[0]. If, on the other hand, your CFE function modifies the array is passed, it's probably better off creating it locally.

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