c - 二维动态数组发送到 C 中的函数

Question

此代码的目的是查看未知大小(从文件中读取)的二维数组(矩阵)是否具有全部相同数字的对角线。如果是这样，函数 checkdiag 应该返回 1。

我正在使用的文件中的数据如下:

3

4 5 6

7 8 9

3 6 7

其中开头的3代表矩阵的大小，(3x3)

我知道它会运行并从文件中收集数据，因为它会使用 fscanf 在 for 循环中打印矩阵。但它每次都会崩溃。我尝试了多种将变量传递给函数的方法，并研究了正在发生的事情，但我在这里遇到了困难。

我是编码新手，尤其是二维数组。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <conio.h>



int checkdiag(int size, int matrix[][size])
{
    int i,sum=0,verif;
    for(i=0;i<size;i++)
    {
       sum += matrix[i][i];
    }
    if(matrix[0][0]==((double)sum/(double)size))
        verif=1;
    else
        verif=0;


   return (verif);
}

int main()
{
    FILE *filename;
    char inputfile[25];
    int howmany,confirmdiag;
    int i,j; //Counter varibles
    int **matrix; // points to the first cell of 2d array [0][0]


    /* Type in exact file to open */
    printf("Please type in the exact name of the data file you with to use and please make  sure it is within the program folder.\nFor example: \"matrix1.txt\"\n");
    gets(inputfile);
    filename = fopen(inputfile,"r");

    if (filename==NULL)
    {
        system("cls");
        printf("\nCould not find the file you've requested, please make sure the file is on the   same partition.\n\n");
        getch();
        exit(0);
    }

    fscanf(filename,"%d",&howmany); //Scanning file to find size of the matrix

    matrix =(int **) calloc(howmany,sizeof(int*)); //Allocating memory for the ROWS of the matrix which are pointers of size (int*)

    for (i=0; i<howmany; i++)
    {
        matrix[i] =(int *) calloc(howmany,sizeof(int));//Allocating memory for the COLUMNS of the matrix which are integers of size (int)
    }

    for(i=0;i<howmany;i++)
    {
        for(j=0;j<howmany;j++)
        {
          fscanf(filename,"%d",&matrix[i][j]);//Scanning the file to fill the matrix array.
        }
    }

    confirmdiag=checkdiag(howmany, **matrix);

    if (confirmdiag==1)
    {
        printf("The matrix is %dx%d and all the numbers on the main diagonal are the same.",howmany,howmany);
    }
    else if (confirmdiag==0)
    {
        printf("The matrix is %dx%d. All the numbers on the main diagonal are not the same.",howmany,howmany);
    }

    for (i=0; i<howmany; i++)
        free (matrix[i]);

    free(matrix);

    return 0;
}

Answer 1

看起来不错。只是一个快速提醒:在您的函数调用中: **matrix 仅将矩阵 matrix(0,0) 的第一个元素发送到该函数，因为您正在取消引用第一列的第一个条目。您需要发送一个指向指针的指针。尝试:

confirmdiag=checkdiag(matrix, howmany, howmany);

对于方法定义:

int checkdiag(int** matrix, int sizeCol, int sizeRow)
{
...
}

祝你好运!