指向结构体数组的指针

Posted 2020-10-24 花兮

#include <iostream>
#include <string>
#include <windows.h>
using namespace std;

//定义一种类型
typedef struct MoreAndMore
{
    char name[66];//68
    int age;//4
    char *subname;//4
} mam;

//创建结构体指针
mam * creatStructArr(int a)
{
    int i = 0, j = 0;//定义遍历数
    mam *arr = (mam *)malloc(3 * sizeof(mam));//分配一个大内存
    //遍历输入赋值结构体内容
    for (i = 0; i < 3; i++)
    {
        cout << "name:" << endl;
        cin >> arr[i].name;//输入name
        cout << "age:" << endl;
        cin >> arr[i].age;//输入age
        char *p = (char *)malloc(100 * sizeof(char));//分配一个小内存
        //遍历初始化值
        for (j = 0; j < 100; j++)
        {
            p[j] = 0;
        }
        cout << "subname:" << endl;
        cin >> *p;//输入subname
        arr[i].subname = p;//把内存指针挂在结构体上面
    }
    return arr;
}

//遍历释放结构体内部malloc的内存
void freeStruct(mam *p,int n)
{
    for (int i = 0; i < n; i++)
    {
        if ((p + i)->subname != NULL)
        {
            free((p + i)->subname);
        }
    }
}

//释放内存
void freeS(mam *p)
{
    if (p != NULL)
    {
        free(p);
    }
}

//打印
void printStruct(mam *p, int n)
{
    int i = 0;
    for (i = 0; i < 3; i++)
    {
        cout << "name:" << (p+i)->name << endl;
        cout << "age:" << (p + i)->age << endl;
        cout << "subname:" << (p + i)->subname << endl;
    }
}
void main()
{
    /*mam xiao = { "axxa",NULL,21 };
    cout << sizeof(mam) << endl;*/
    int i = 0;//遍历数
    int n = 3;//要自动生成的个数
    mam *p = creatStructArr(n);//开始生成 返回指针
    printStruct(p, n);//打印
    freeStruct(p, n);//释放
    p = NULL;//避免野指针

    system("pause");
}