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garin
Asked:2020-10-16 19:48:05 +0000 UTC2020-10-16 19:48:05 +0000 UTC

C：删除一行二维数组时内存泄漏。瓦尔格林

  • 772

请。

程序删除矩阵中的一行。一切正常，但无法从已删除的行中释放内存。

请告诉我，这怎么办？

#include "cdio.h"
#include "func.h"

int main()
{
    long int **matrix = NULL;
    size_t n = 5;
    size_t m = 4;

    matrix = matrix_allocate(n, m);

    for (size_t i = 0; i < n; i++)
        for (size_t j = 0; j < m; j++)
            matrix[i][j] = rand() % 100;

    puts("OLD MATRIX:");
    print_matrix(matrix, n, m);

    int pos = 0;

    puts("enter position:");
    scanf("%d", &pos);

    for (size_t i = pos; i < n-1; i++)
        matrix[i] = matrix[i+1];


    n--;

    long int **temp = realloc(matrix, n * sizeof(long int));

    if (temp)
    {
        matrix = temp;
        temp = NULL;
    }




    puts("NEW MATRIX:");
    print_matrix(matrix, n, m);

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

    free(matrix);

    return 0;
}

==5203== HEAP SUMMARY:
==5203==     in use at exit: 32 bytes in 1 blocks
==5203==   total heap usage: 9 allocs, 8 frees, 2,280 bytes allocated
==5203== 
==5203== LEAK SUMMARY:
==5203==    definitely lost: 32 bytes in 1 blocks
==5203==    indirectly lost: 0 bytes in 0 blocks
==5203==      possibly lost: 0 bytes in 0 blocks
==5203==    still reachable: 0 bytes in 0 blocks
==5203==         suppressed: 0 bytes in 0 blocks
c

1 个回答

  1. Best Answer

    键入错误时realloc：

    long int **temp = realloc(matrix, n * sizeof(long int));

    数组中的类型是指针，而不是long int.

    long int **temp = realloc(matrix, n * sizeof(long int * ));

    Чтобы освободить память строки нужно просто сделать free。

    scanf("%d", &pos);

free(matrix[pos]);

    for (size_t i = pos; i < n-1; i++)
        matrix[i] = matrix[i+1];
    • 0

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