结构体与指针

#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>

struct data
{
    int num;
};
void main()
{
    struct data(*p)[10] = malloc(sizeof(struct data) * 90);// 动态分配二维数组
    int k = 0;
    for (int i = 0; i < 9; i++)
    {
        for (size_t j = 0; j < 10; j++)
        {
            printf("%4d",(p[i][j]).num=k++);
        }
        printf("\n");
    }

    system("pause");
}

////////////////////////////////////////////////////////////////////////////

void main()
{
    struct data **pp;//分块数组
    pp = malloc(sizeof(struct data *) * 10);//先分配指针数组
    int n = 0;
    for (int i = 0; i < 10; i++)
    {
        pp[i] = malloc(sizeof(struct data) * (i + 3));//每一个指针分配内存
        for (struct data *newp = pp[i]; newp < pp[i] + (i + 3); newp++)
        {
            printf("%d  ", newp->num = n++);
        }
        printf("\n");
    }

    system("pause");
}

////////////////////////////////////////////////////////////////////////

void main()
{
    struct data *p = alloca(sizeof(struct data) * 10);
    int m = 0;
    for (struct data *newp = p; newp < p + 10;newp++)
    {
        printf("%d ",newp->num = m++);
    }
    system("pause");
}