使用二级指针，初始化一级指针

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
enum
{
    Success,NameErr,SexErr,StrNumErr,ScoreErr
};
typedef struct stu
{
    char *name;
    char *sex;
    char *strNum;
    float *score;
}STU;
int init(STU ** p)
{
    *p = (STU *)malloc(sizeof(STU));//*p就是ps,申请一块空间里面存放4个不同类型的指针，将首地址赋值给ps
    //初始化一级指针，使这4个不同类型的指针都有所指向
    (*p)->name = (char *)malloc(sizeof(100));
    if((*p)->name == NULL)
        return NameErr;
    (*p)->sex = (char *)malloc(sizeof(char));
    if((*p)->sex == NULL)
        return SexErr;
    (*p)->strNum = (char *)malloc(sizeof(30));
    if((*p)->strNum == NULL)
        return StrNumErr;
    (*p)->score = (float *)malloc(sizeof(float));
    if((*p)->score == NULL)
        return ScoreErr;
    return Success;
}
int main(void)
{
    STU * ps = NULL;

    int ret = init(&ps);
    if(ret != Success)
        return -1;
    strcpy(ps->name,"wahaha");
    *(ps->sex) = 'x';
    strcpy(ps->strNum,"语文");
    *(ps->score) = 66.5;

    printf("姓名：%s
性别：%c
科目：%s
分数：%.2f
",ps->name,*(ps->sex),ps->strNum,*(ps->score));
    return 0;
}