Question

I'm trying to create a dynamic set abstract data type, based on a dynamic array. However, I get a compiler an error when an array is full and I invoke the realloc, which are: realloc(): invalid next size My code is as follows:

struct arraystack{
    int top;
    int capacity;
    void **array;
    size_t data_size; //size of my data type
};

struct arraystack * createStack(int capacity,size_t size_data_type){
    struct arraystack *stack= (struct arraystack*) malloc(sizeof(struct arraystack));
    stack->capacity=capacity;
    stack->top=-1;
    stack->data_size=size_data_type;
    stack->array= malloc(stack->capacity*size_data_type);
    return stack;  
}

void push(struct arraystack *stack, void* data){
     if(isFull(stack)){
         printf("Invoco realloc\n");
         stack->capacity=(stack->capacity*2)+1;
         void **tmp=realloc(stack->array,(stack->capacity*stack->data_size)); //this line gives me an error
         if(!tmp){
             printf("Attenzione memoria insufficente!\n");
             exit(1);
         }
         stack->array=tmp;
     }
     stack->array[++stack->top]=data;
     printf("%d pushed to stack\n", data); 
}

int isFull(struct arraystack *stack){
    return stack->top == stack->capacity - 1; 
}

int main(){
    struct arraystack *tmp=createStack(5,sizeof(int));

    int i;
    for(i=0;i<=20;i++){
        push(tmp,i);
        printf("top-> %d memoria allocata->%d\n",tmp->top,tmp->capacity);
    }

}

Answer 1

不清楚您是否需要Arc或void**。

此行有问题：void*

您永远不会正确初始化此存储区。它应该为您拥有对象的stack->array= malloc(stack->capacity*size_data_type);分配空间。这与所指向项目的数据大小无关。每个此类指针都需要初始化。您需要跟踪指针的总数以及每个指向项目的大小。

或者，如果要指向一维数组或单个对象，则应该将void*改为void**。

void*看起来很腥，这使索引0未被初始化。

确保包括stack->array[++stack->top]=data;，否则您会遇到石器时代C90编译器的严重错误，这些错误会隐藏在演员表中。

Error realloc with Dynamic Array of Void Pointers

1 个答案: