如何使結構點本身沒有Valgrind的抱怨

Question

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

struct Person{ 
    char *name; 
    char sex; 
    int age; 
    struct Person *ancestor;  
    int n; 
}; 

void p_person(struct Person *this); 

struct Person *stack_init() 
{ 
    struct Person *this=malloc(sizeof(struct Person)); 
    assert(this!=NULL); 

    this->name=strdup("NULL"); 
    this->sex='0'; 
    this->age=-1; 
    this->ancestor=NULL; 
    this->n=1; 

    return this; 
} 

struct Person *pushPerson(struct Person *this, char *name, char sex, int age) 
{ 
    assert(this!=NULL); 
    int n=this->n+1; 
    this=realloc(this,sizeof(struct Person)*n); 

    this[n-1].name=strdup(name); 
    this[n-1].sex=sex; 
    this[n-1].age=age; 
    this[n-1].ancestor=&this[n-2]; 

    printf("pushing new person onto stack\n"); 
    printf("stack increasing to %d\n",this->n); 
    p_person(&this[n-1]); 

    this->n=this->n+1; 
    /*p_person(this[n-1].ancestor); //it works*/ 
    printf("----------------\n\n"); 

    return this; 
} 

struct Person *popPerson(struct Person *this) 
{ 
    assert(this!=NULL); 
    printf("Person being popped:\n"); 
    p_person(&this[this->n-1]); 
    printf("resizing stack to %d\n", this->n-2); 
    printf("----------------\n\n"); 
    free(this[this->n-1].name); 
    int n=this->n-1; 
    this=realloc(this,sizeof(struct Person)*n); 

    this->n=this->n-1; 

    return this; 
} 

void p_person(struct Person *this) 
{ 
    printf("Name: %s\n",this->name); 
    printf("Sex: %c\n",this->sex); 
    printf("Age: %d\n",this->age); 
} 

void p_person_stack(struct Person *this) 
{ 
    printf("printing stack...........\n"); 
    struct Person *current; 
    int i; 
    for(i=1;i<this->n;i++) 
    { 
     current=&this[i]; 
     p_person(current); 
     printf("---------\n"); 
    } 
    printf("stack printed~~~~~~~~~~\n\n"); 
} 

void d_person_stack(struct Person *this) 
{ 
    int i; 
    for(i=0;i<this->n;i++) 
     free(this[i].name); 
    free(this); 
} 

int main(int argc, char *argv[]) 
{ 
    struct Person *people=stack_init(); 

    people=pushPerson(people,"Mojo jojo", 'M', 33); 
    people=pushPerson(people,"Ali Zaheeruddin", 'M', 24); 
    people=pushPerson(people,"Mahdi Moosa", 'M', 24); 
    people=pushPerson(people,"Solid Snake", 'M', 51); 

    d_person_stack(people); 

    return 0; 
} 

p_person（&人[N]），其中n是堆棧

p_person（人[N]範圍內的作品，未經Valgrind的抱怨罰款。祖先）使valgrind抱怨大小爲x的無效讀取取決於它在結構中讀取的內容Person例如char性別將爲x = 1 這裏的例外是當n是堆棧的結尾時（在這種情況下爲4）valgrind會沒有抱怨，對於n的所有情況，結果將被打印罰款。

這是什麼，如果我做p_person（人[N] .ancestor），其中n 小於堆的端面的valgrind會說一個例子

大小8 名稱的無效讀：阿里Zaheeruddin 的無效讀取大小1 性別：男 的無效讀取大小4 年齡：24

Answer 1

this[n-1].ancestor=&this[n-2]; 

當你有0或1的陣列中的現有元素的n 2而來的陣列開始的下方，使對我的無效閱讀該地址（8字節）。