关于野指针的一些问题

#include<stdio.h>

#include<stdlib.h>

#include<string.h>



struct student  

{  

    int num;  

    char name[20];  

    float score[3];  

};  



int main()  

{  

    

    struct student *stu;  

	//stu =(struct student*) malloc(sizeof(struct student));

    strcpy(stu->name, "Tom");  

    

    stu->score[0] = 67.5; 

    stu->num = 123;

    printf("stu->num =%d",stu->num);

    printf("stu->score[0] =%f",stu->score[0]);

    printf("stu->name=%s\n",stu->name);

    return 0;  

}