结构体嵌套一级指针内存模型20200222

一、代码如下：

#define  _CRT_SECURE_NO_WARNINGS 
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

//定义一个结构体类型
typedef struct Teacher
{
	char name[16];
	int age;
	int id;
	char* bname;
}Teacher;
//申请结构体数组内存空间
Teacher* getMem(Teacher* parray, int num)
{
	int i = 0;
	Teacher* tmp = parray;
	//==>Teacher parray[3];
	tmp = (Teacher*)malloc(num * sizeof(Teacher));
	if (tmp == NULL)
	{
		printf("func getMem() malloc error\n");
		return NULL;
	}
	memset(tmp, 0, num * sizeof(Teacher));
	for (i = 0; i < num; i++)
	{
		tmp[i].bname = (char*)malloc(16);
		if (tmp[i].bname == NULL)
		{
			printf("func getMem() malloc error\n");
			return NULL;
		}
		//malloc内存之后要及时初始化
		memset(tmp[i].bname, 0, 16);
	}
	return tmp;
}
//给数组年龄及别名内存空间赋值
void set_value(Teacher* parray, int num)
{
	int i = 0;
	Teacher* tmp = parray;
	for (i = 0; i < num; i++)
	{
		printf("\nplease input age:");
		scanf("%d", &tmp[i].age);
		printf("\nplease input bname:");
		scanf("%s", tmp[i].bname);
	}
}
//打印数据
void print_age_bname(Teacher* parray, int num)
{
	int i = 0;
	for (i = 0; i < num; i++)
	{
		printf("%d\n", parray[i].age);//步长的问题
		printf("%s\n", parray[i].bname);
	}
}
//排序
void sortArray(Teacher* parray, int num)
{
	int i = 0, j = 0;
	Teacher tmp;
	for (i = 0; i < num; i++)
	{
		for (j = i + 1; j < num; j++)
		{
			//由小到大
			if (parray[i].age > parray[j].age)
			{
				tmp = parray[i];
				parray[i] = parray[j];
				parray[j] = tmp;
			}
		}
	}
}
//释放申请的内存
void free_Mem(Teacher* parray, int num)
{
	int i = 0;
	Teacher* tmp = parray;
	if (tmp == NULL)
	{
		return;
	}
	for (i = 0; i < num; i++)
	{
		if (tmp[i].bname != NULL)
		{
			free(tmp[i].bname);
		}
	}
	if (tmp != NULL)
	{
		free(tmp);
	}
}
//
int main()
{
	//1.定义一个结构体指针
	Teacher* pArray = NULL;
	int num = 3;
	pArray = getMem(pArray, num);
	set_value(pArray, num);
	//2.打印排序前
	printf("sort before:\n");
	print_age_bname(pArray, num);
	//3.进行排序操作
	sortArray(pArray, num);
	//4.打印排序后
	printf("sort after:\n");
	print_age_bname(pArray, num);
	//5.释放内存
	free_Mem(pArray, num);
	printf("\n");
	system("pause");
	return 0;
}

二、内存模型图：