int** result = malloc(sizeof (int *) * mid);
时间: 2023-07-23 09:10:55 浏览: 53
这段代码是使用动态内存分配(`malloc`函数)为一个二维整型数组分配内存空间。
首先,`sizeof(int *)`是指针类型`int *`的大小,即指向整型的指针所占用的字节数。
然后,`sizeof(int *) * mid`将指针类型的大小乘以`mid`,得到需要分配的二维数组的行数。
接下来,`malloc(sizeof(int *) * mid)`将为二维数组的行分配内存空间。
最后,将分配的内存空间的起始地址赋值给指针变量`result`,该指针类型是`int **`,即指向指针类型`int *`的指针。
总结起来,这段代码的作用是动态地为一个二维整型数组分配内存空间,并将起始地址保存在指针变量`result`中。这样,我们就可以使用`result`来访问和操作这个二维数组。需要注意的是,在使用完这块内存空间后,应该使用`free(result)`来释放它,以避免内存泄漏。
相关问题
int *returnSize = malloc(sizeof(int))
引用\[2\]中提到,语句int *returnSize = malloc(sizeof(int))给指针变量returnSize分配了一个整型存储空间。这意味着returnSize指针变量现在可以用来存储一个整数值。需要注意的是,在使用指针变量之前,必须先为其分配相应的内存空间,否则会导致程序异常。
#### 引用[.reference_title]
- *1* [(int*) malloc(SIZE * sizeof(int)) 惨痛的教训](https://blog.csdn.net/Ssure/article/details/8977386)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^koosearch_v1,239^v3^insert_chatgpt"}} ] [.reference_item]
- *2* [C语言(int *)malloc(sizeof(int))的作用与意思](https://blog.csdn.net/u014183815/article/details/107336736)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^koosearch_v1,239^v3^insert_chatgpt"}} ] [.reference_item]
- *3* [‘sizeof’ on array function parameter ‘array’ will return size of ‘int*’](https://blog.csdn.net/weixin_43737395/article/details/123233550)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^koosearch_v1,239^v3^insert_chatgpt"}} ] [.reference_item]
[ .reference_list ]
int *nums=malloc(count *sizeof(int))
This code snippet allocates dynamic memory in the heap for an array of integers of size "count". The pointer "nums" points to the first element of the array.
The "sizeof(int)" operator returns the size of an integer in bytes, and by multiplying it with "count", we get the total amount of memory required for the array.
The "malloc()" function allocates the requested amount of memory and returns a pointer to the first byte of the allocated block. In this case, the "malloc()" function returns a void pointer, which is then typecasted to an integer pointer and assigned to "nums".