我试图将N元数组传递给C++中的函数。

保持简单,对于一维数组,这是一个:

#include <iostream>

template <size_t N> int sign(int(&arr)[N], int i)
{
    return (arr[i] >= 0) ? +1 : -1 ;
}

int main(int argn, char** argv)
{
    const int SIZE = 2;

    int (*arr1d) = new int[SIZE];
    arr1d[0] = 12;
    arr1d[1] = -1;

    std::cout << "sign 0 : " << sign(arr1d, 0) << std::endl ;
    std::cout << "sign 1 : " << sign(arr1d, 1) << std::endl ;
}

但这不会编译:
Sign.cpp:17:50: error: no matching function for call to ‘sign(int*&, int)’
     std::cout << "sign 1 : " << sign(arr1d, 1) << std::endl ;
                                              ^
Sign.cpp:3:29: note: candidate: template<long unsigned int N> int sign(int (&)[N], int)
 template <size_t N> int sign(int(&arr)[N], int i)
                         ^~~~
Sign.cpp:3:29: note:   template argument deduction/substitution failed:
Sign.cpp:17:50: note:   mismatched types ‘int [N]’ and ‘int*’
     std::cout << "sign 1 : " << sign(arr1d, 1) << std::endl ;

我不介意不使用模板(这似乎是这里的问题)。

有什么建议吗?

2D情况下的相同错误:
#include <iostream>

template <size_t M, size_t N> int sign(int(&arr)[M][N], int i, int j)
{
    return (arr[i][j] >= 0) ? +1 : -1 ;
}

int main(int argn, char** argv)
{
    const int SIZE = 2;

    int (*arr2d)[SIZE] = new int[SIZE][SIZE];
    arr2d[0][0] = 12;
    arr2d[0][1] = -1;
    arr2d[1][0] = 32;
    arr2d[1][1] = -4;

    std::cout << "sign 0 1: " << sign(arr2d, 0, 1) << std::endl ;
}

最佳答案

尝试将指向数组的指针传递给sign函数。

template <size_t M, size_t N>
int sign(int(*arr)[N], int i, int j)
{
    return (arr[i][j] >= 0) ? +1 : -1 ;
}

然后,您可以按以下方式调用sign函数:
std::cout << "sign 0 1: " << sign<SIZE, SIZE>(arr2d, 0, 1) << std::endl ;

关于c++ - 将基于堆的N元数组引用传递给函数,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/54519958/

10-11 22:45
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