C++ 在链式 struct 中为数组释放内存

正如在另一个答案中已经指出的，问题是您的链表的头 node 没有被malloc分配.因此，您不能在该 node 上呼叫free.

然而，与其他答案不同的是，我不建议您通过在释放内存时省略头 node 来解决问题，而是建议您重新构造程序，以便平等对待所有 node (包括头 node )，以便头 node 的内存也按malloc%分配:

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


struct groupingOrder {
    int *taxa;
    size_t groupeSize;
    long double distance;
    struct groupingOrder* next;
};


void addGroup( struct groupingOrder** HEAD, int * groupe, size_t groupeSize, long double distance ) {

    struct groupingOrder** temp = HEAD;
    // Make "temp" point to the "next" member of the last node of
    // the list, or if the list is empty, make "temp" point to
    // the pointer to the head node (which has the value NULL).
    while( (*temp) != NULL ) {
        temp = &(*temp)->next;
    }
    // Allocating space for the unit structure
    struct groupingOrder* nouveau = malloc( sizeof( struct groupingOrder ) );
    nouveau->distance = distance;
    nouveau->groupeSize = groupeSize;
    // Allocating variable space for the list of taxa to be stored
    nouveau->taxa = malloc( groupeSize * sizeof( int ) );
    for( int i = 0; i < groupeSize; i++) {
        nouveau->taxa[i] = groupe[i];
    }
    // Specifying the NULL pointer to label the last unit
    nouveau->next = NULL;
    // Linking the new unit structure to the previous one
    *temp = nouveau;
}


void dumpGroupingOrder( struct groupingOrder** HEAD ) {

    struct groupingOrder* temp = *HEAD;
    while( temp != NULL ) {

        // Copying the address of the current unit
        struct groupingOrder* dumpTarget = temp;
        // Storing the address of the next unit before dumping the
        //  current one.
        temp = temp->next;

        // Dumping the current unit and all its allocated variables
        if ( dumpTarget->taxa != NULL ) {
            free( dumpTarget->taxa );
            printf( " #" );
        }
        free( dumpTarget );
        printf( "* " );
    }

    // Mark linked list as empty
    *HEAD = NULL;
}


void showGroupingOrder( struct groupingOrder* HEAD ) {

    for ( struct groupingOrder* temp = HEAD; temp != NULL; temp = temp->next ) {
        
        for( int i = 0; i < temp->groupeSize; i++) {
            printf( " %d", temp->taxa[i] );
        }
        printf( " %Lf\n", temp->distance );
    }
}



int main() {
  
    size_t groupeSize[6] = { 2,2,4,2,5,7 };
    int groupes[][7] = { {2,3}, {5,1}, {2,3,5,1}, {7,4}, {2,3,5,1,6}, {2,3,5,1,6,7,4} };

    struct groupingOrder *HEAD = NULL;
  
    for ( int i = 0; i < 6; i++ ) {

        addGroup( &HEAD, groupes[i], groupeSize[i], 0.0003 );
    }

    showGroupingOrder( HEAD );
    printf( "\n\n" );
    dumpGroupingOrder( &HEAD );
  
    return 0;
}

我有必要修改函数main和addGroup.我还修改了其他两个函数，但这些更改是不必要的.

该程序的输出如下:

 2 3 0.000300
 5 1 0.000300
 2 3 5 1 0.000300
 7 4 0.000300
 2 3 5 1 6 0.000300
 2 3 5 1 6 7 4 0.000300


 #*  #*  #*  #*  #*  #*