C Language Study - 结构体成员指针初始化

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结构体成员指针初始化

不可以正确运行的初始化方式（1）：

#include <stdio.h>
#include <string.h>
#include <malloc.h>
//#include "a.h"

//char a[100];
struct stu
{
    char* name;
    int num;
}*pst,st;

void init_pst()
{
    pst = (struct stu *)malloc(sizeof(struct stu));
    //pst->name = (char*)malloc(sizeof(char*));
    //pst->num = 0;
}

void free_pst()
{
    free(pst);
}

int main(void)
{
    //strcpy(pst->name,"Jacy");
    //pst->num = 99;
    init_pst();
    //test();
    strcpy(pst->name,"Jacy");
    pst->num = 99;
    printf("%s %c",pst->name,pst->num);
    free_pst();
    return 0;
}

#include <stdio.h>
#include <string.h>
#include <malloc.h>
//#include "a.h"

//char a[100];
struct stu
{
    char* name;
    int num;
}*pst,st;

void init_pst()
{
    NULL;
    //pst = (struct stu *)malloc(sizeof(struct stu));
    //pst->name = (char*)malloc(sizeof(char*));
    //pst->num = 0;
}

void free_pst()
{
    free(pst);
}

int main(void)
{
    //strcpy(pst->name,"Jacy");
    //pst->num = 99;
    init_pst();
    //test();
    strcpy(pst->name,"Jacy");
    pst->num = 99;
    printf("%s %c",pst->name,pst->num);
    free_pst();
    return 0;
}

可以正确运行的初始化方式：

#include <stdio.h>
#include <string.h>
#include <malloc.h>
//#include "a.h"

//char a[100];
struct stu
{
    char* name;
    int num;
}*pst,st;

void init_pst()
{
    pst = (struct stu *)malloc(sizeof(struct stu));
    pst->name = (char*)malloc(sizeof(char*));
    pst->num = 0;
}

void free_pst()
{
    free(pst);
}

int main(void)
{
    //strcpy(pst->name,"Jacy");
    //pst->num = 99;
    init_pst();
    //test();
    strcpy(pst->name,"Jacy");
    pst->num = 99;
    printf("%s %c",pst->name,pst->num);
    free_pst();
    return 0;
}

以后的编程习惯：结构体一定义，立马进行初始化内存分配。

C Language Study - 结构体成员指针初始化

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原文地址：http://blog.csdn.net/oimchuan/article/details/44035137