c - 为具有指针成员的指针结构分配内存

Question

我正在尝试使用具有指针成员的结构指针来读取和打印。所以我试图读取和打印双结构指针数组。我尝试了以下操作，但它给我错误消息“访问冲突写入位置(内存中的某处)”

如何为此动态分配内存？

#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif

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

typedef struct template{
char *name;
int  *birthdate;
int *phoneNum;

} detailsOf;

void inputValue(detailsOf **person, int maxSize);

int main() {

detailsOf **person;
int maxSize = 0, menu = 0;

printf("Max:");
scanf("%d", &maxSize);


person = (detailsOf **)malloc(maxSize * sizeof(detailsOf **));
if (person == NULL) {
    printf("Failed to allocate");
    exit(0);
}
for (int i = 0; i < maxSize; i++) {
    person[i]->name = (char *)calloc(21, sizeof(char ));
    person[i]->birthdate = (int *)calloc(8, sizeof(int ));
    person[i]->phoneNum = (int *)calloc(16, sizeof(int ));
}

inputValue(person, maxSize);

for (int i = 0; i < maxSize; i++) {
    free(person[i]);
    for (int j = 0; j < 21; j++) {
        free(person[i]->name[j]);
    }
    for (int j = 0; j < 15; j++) {
        free(person[i]->phoneNum[j]);
    }
    for (int j = 0; j < 8; j++) {
        free(person[i]->birthdate[j]);
    }
}
    return 0;
}
void inputValue(detailsOf **person, int maxSize) {
    for (int i = 0; i < maxSize; i++) {
        printf("Name of %d", i + 1);
        scanf("%s", person[i]->name);
          for (int j = 0; j < 8; j++) {
             printf("Birth %d:", i + 1);
             scanf("%d", person[i]->birthdate[j]);
     } 
     for (int k = 0; k < 8; k++) {
         printf("Phone %d:", i + 1);
         scanf("%d", person[i]->phoneNum[k]);
      }
   }
    printf("SUCCESS\n");
}

Answer 1

person = (detailsOf **)malloc(maxSize * sizeof(detailsOf **));

应该是

person = malloc(maxSize * sizeof(detailsOf *));

然后，分配的内存用于保存指向 detailsOf 的指针，但您永远不会为每个 detailsOf 分配内存

for(int i=0; i<maxSize; i++)
{
   person[i]=malloc(sizeof(detailsOf));
}

您还应该释放内存

for (int i = 0; i < maxSize; i++)
{
    free(person[i]->name);
    free(person[i]->phoneNum);
    free(person[i]->birthdate);
    free(person[i]);
}
free(person);

请记住，释放时只需将 free 调用与 malloc 调用相匹配。