[用C编写的2D数组问题

Question

我有以下代码，仅显示第二行两次。不知道为什么。我的输入是1 4 5 2 3 0，而我的输出是2 3 0 2 3 0。所以下面是我的代码，我想请用户输入行数和列数。然后，用户输入元素以填充数组。最后一步是要打印出数组。

#include <stdio.h>
//#define ROW_SIZE 2
//#define COL_SIZE 3

int ROW_SIZE = 0;
int COL_SIZE = 0;

int main()
{
    int matrix[ROW_SIZE][COL_SIZE];
    int row;
    int col;

    printf("\n Enter the number of columns and rows: ");
    scanf("%d %d", &ROW_SIZE, &COL_SIZE);

    printf("Enter elements in matrix of size %dx%d \n", ROW_SIZE, COL_SIZE);

    /* Outer loop to iterate through each row */
    for(row=0; row<ROW_SIZE; row++)
    {
        /* Inner loop to iterate through columns of each row */
        for(col=0; col<COL_SIZE; col++)
        {
            /* Input element in array */
            scanf("%d", &matrix[row][col]);
        }
    /* 
     * Print all elements of array
     */
      printf("\nElements in matrix are: \n");
      for(row=0; row<ROW_SIZE; row++)
     {

          for(col=0; col<COL_SIZE; col++)
          {
            printf("%d", matrix[row][col]);
          }
          printf("\n");
     }
     return 0;
}

Answer 1

您不能声明具有0个元素的可变长度数组。

int ROW_SIZE = 0;
int COL_SIZE = 0;

int main()
{
int matrix[ROW_SIZE][COL_SIZE];
//...

您必须在输入ROW_SIZE和COL _SIZE的值后声明数组。

printf("\n Enter the number of columns and rows: ");
scanf("%d %d", &ROW_SIZE, &COL_SIZE);
int matrix[ROW_SIZE][COL_SIZE];
//...

此外，在文件作用域中定义变量ROW_SIZE和COL_SIZE也没有意义。最好在函数main的块范围内定义它们。

也有错字。您忘记了外循环的右括号

/* Outer loop to iterate through each row */
for(row=0; row<ROW_SIZE; row++)
{
    /* Inner loop to iterate through columns of each row */
    for(col=0; col<COL_SIZE; col++)
    {
        /* Input element in array */
        scanf("%d", &matrix[row][col]);
    }

Answer 2

真正解决问题的是移动此代码块。 int matrix[ROW_SIZE][COL_SIZE];

在这段代码下看起来像这样

`int main()
{
int matrix[ROW_SIZE][COL_SIZE];
int row;
int col;

`printf("\n Enter the number of columns and rows: ");
scanf("%d %d", &ROW_SIZE, &COL_SIZE);`