深拷贝和浅拷贝

 

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

typedef struct Teacher
{
    char name[64];
    int age;
    char *pname2;
}teacher;

/*
编译器的=号操作会把指针变量的值，从from copy到to
但不会把指针变量所值的内存空间给copy过去 
这就是浅拷贝的概率

对于结构体中含有一级指针或二级指针
需要执行深拷贝，即显示分配内存，并且执行指针赋值操作
strcpy或者memcpy 
*/
void copyTeacher(Teacher *to, Teacher *from)
{
    *to = *from;
    
    to->pname2 = (char *)malloc(100);
    strcpy(to->pname2, from->pname2);
}

int main()
{
    Teacher t1;
    Teacher t2;
    
    strcpy(t1.name,"name1");
    t1.age = 18;
    t1.pname2 = (char *)malloc(100);
    strcpy(t1.pname2,"ssss");
    
    copyTeacher(&t2,&t1);
    
    printf("%s\n%d\n%s",t2.name,t2.age,t2.pname2);
    
    if(t1.pname2 != NULL)
    {
        free(t1.pname2);
        t1.pname2 = NULL;
    }
    if(t2.pname2 != NULL)
    {
        free(t2.pname2);
        t2.pname2 = NULL;
    }
    
    return 0;
}