c - 在c中交换二维数组的行

Question

目前我想知道如何交换二维数组中已有的值，在本例中我设法交换它们，但是，我似乎无法将它们交换回来......如何我可以让程序来回交换数组的值吗？

代码:

#include <stdio.h>

void main()
{
    //declaration of values
    int d = 0;
    char value;
    float list[5][6], swaplist[5][6];
    float average_odd, sum = 0, average_even, sum1 = 0;

    //Command list so that the user knows what he can do in this program
    printf("Command list:\t \n\nCommand: \t\t Output: ");
    printf("\n  \"A\"  \t\t Declare values of a list.\n  \"O\"  \t\t Obtain the average value of the even and odd column\n\t\t values in the list.\n");
    printf("  \"I\"  \t\t Exchange the values on the even columns with the odd ones.\n  \"P\"  \t\t Print the values of the list.\n  \"S\"  \t\t End program.");
    //========================================================================================================
    while (d != 1)
    {
        printf("\n\nInsert value: ");
        scanf(" %c", &value);
        //=========================================================================================================
        if (value == 'a' || value == 'A')
        {
            for (int i = 0; i < 5; i++)
            {
                for (int j = 0; j < 6; j++)
                {
                    printf("Insert value of element %d in column %d: ", i + 1, j + 1);
                    scanf("%f", &list[i][j]);
                    swaplist [i][j] = list[i][j];
                }
            }
        }
        //=========================================================================================================
        if (value == 's' || value == 'S')
        {
            d++;
        }
        //=========================================================================================================
        if (value == 'P' || value == 'p')
        {
            for (int i = 0; i < 5; i++)
            {
                for (int j = 0; j < 6; j++)
                {
                    printf("%2.2f   ", list[i][j]);
                }
                printf("\n");
            }
        }
        //========================================================================================================
        if (value == 'o' || value == 'O')
        {
            for (int i = 0; i < 5; i++)
            {
                for (int j = 0; j < 6; j = j + 2)
                {
                    sum += list[i][j];
                }
            }
            for (int i = 0; i < 5; i++)
            {
                for (int j = 1; j < 6; j = j + 2)
                {
                    sum1 += list[i][j];
                }
            }
            average_even = sum1 / 15;
            printf("The average of the  even columns = %.2f\n", average_even);
            average_odd = sum / 15;
            printf("The average of the odd columns = %.2f\n", average_odd);
        }
        //=======================================================================================================
        if (value == 'i' || value == 'I')
        {
            for (int i = 0; i < 5; i++)
            {
                for (int j = 0; j < 6; j = j + 2)
                {
                    list[i][j] = swaplist[i][j+1];
                }
            }
            for (int i = 0; i < 5; i++)
            {
                for (int j = 1; j < 6; j = j + 2)
                {
                    list[i][j] = swaplist[i][j - 1];
                }
            }
        }
    }
}

Answer 1

交换后，您不会更改交换列表的状态。首先，交换列表是未交换矩阵的副本。您不会更改它来反射(reflect)矩阵中的更改，也不会跟踪任何其他状态。

您实际上并不需要交换列表。我建议您定期交换相邻列的单元格:

    if (value == 'i' || value == 'I') {
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 6; j = j + 2) {
                float swap = list[i][j];

                list[i][j] = list[i][j + 1];
                list[i][j + 1] = swap;
            }
        }
    }

这将在重复交换时切换矩阵。