一步一步学数据结构之（动态申请二维数组）

MGraph* MGraph_Create(MVertex** v, int n)
{
TMGraph* ret = NULL;

if((NULL!=v) && (0<n))
{
ret = (TMGraph*)malloc(sizeof(TMGraph));

if(NULL != ret)
{
int* p = NULL;

ret->count = n;
//通过二级指针动态申请一维指针数组
ret->v = (MVertex**)malloc(sizeof(MVertex*) * n);
ret->matrix = (int**)malloc(sizeof(int*) * n);

//通过一级指针申请数据空间
//calloc函数把申请的数据空间全清0
p = (int*)calloc(n * n, sizeof(int));

if((NULL!=ret->v) && (NULL!=ret->matrix) && (NULL!=p))
{
int i = 0;

for(i=0; i<n; i++)
{//把指针数组和数据空间连接起来
ret->v[i] = v[i];
ret->matrix[i] = p + i* n;
}
}
else
{
free(ret->v);
free(ret->matrix);
free(p);
free(ret);

ret = NULL;
}
}
}

return ret;
}