在函数之间传递相同的数组

Question

我正在为我的 class 编写一个 C++ 程序来计算一组输入边的 MST（最小生成树）。到目前为止，我已经编写了一些函数，但在尝试传递一个包含最小生成树的 "edges" 的数组时遇到了困难。如何将此数组从 readGraph 函数传递到 insertEdge 函数？

当我尝试使用“&”时，编译器显示此错误：

error: cannot convert 'int**' to 'int*' for argument '4' to 'void insertEdge(int, int, int, int*)'|

Instructions for the assignment

#include "iostream"
#include <cstdio>
#include "equiv.h"
#include <string.h>
using namespace std;

// Edge structure which creates 3 integer variables(vert1, vert2, weight)
// and uses a constructor to initialize these variables.
// "vert1" & "vert2" hold 2 vertex numbers and "weight" holds the weight of a edge.

struct Edge
{
    int vert1;
    int vert2;
    int weight;

   Edge() : vert1(0), vert2(0), weight(0)
   {
   }
};
const int maxEdges = 100;
struct Graph
{
    int vertGraph;
    int edgeGraph;
    int edgeArray [maxEdges];
    int physicalSizeArray;
   Graph(int nv) : vertGraph(0), edgeGraph(0), edgeArray(), physicalSizeArray(0)
   {
   }
};
// insertEdge(u, v, w, g) inserts an edge of weight w between vertices
// u and v into graph g.
//
// If there is not enough room in g to add the edge, then
// insertEdge does nothing.
void insertEdge(int u,int v,int w,int g[])
{
    int arrayPosition = 0;
    for (int i = 0; i <= maxEdges; i++) 
    {
        if (g[i] == 0) {
            if(arrayPosition == 0)
            {
                g[i] = u;
                arrayPosition++;
            }
           else if(arrayPosition == 1)
           {
                g[i] = w;
                arrayPosition++;
           }
           else if(arrayPosition == 2)
           {
                g[i] = v;
                break;
           }
        }
    }
}
void readGraph(int G[])
{
    Edge p1;
    bool nextEdge = true;
    int i = 0;
    cout << "Enter number of vertices: ";
    cin >> i;
    cout << "Enter two vertices separated by a space and followed by a weight for edge: ";
    while(nextEdge)
    {
        cin >> (p1.vert1, p1.vert2, p1.weight);
        insertEdge(p1.vert1,p1.vert2,p1.weight,G);
        if(p1.vert1 == 0)
        {
            nextEdge = false;
        }
   }
}

int main()
{
    int arrayTest[20];
    readGraph(&arrayTest);
    return 0;
}

Answer 1

可以通过三种方式将数组作为参数传递给函数：

1. void function(int* param)

2. void function(int param[20]) 

3. void function(int param[])

所有这三种可能的声明都会产生类似的结果，因为它们都告诉编译器将接收一个整数指针作为函数的参数。

How do I pass this array from the readGraph function to insertEdge function?

readGraph(arrayTest);

您不应传递数组的内存地址，而应传递数组本身，即通过指定不带索引的数组名称来指向数组的指针。

还要注意 C++ 不对形式参数执行边界检查，因此最好选择 std::array 或 std::vector 而不是 c-array。

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