Question

我有一个结构（在C语言中）声明如下：

struct readyQueue
{
    int start;
    int total_CPU_burst;
    int CPU_burst;
    int CPU_bursted;
    int IO_burst;
    int CPU;
    struct readyQueue *next;
};
struct readyQueue *readyStart = NULL;
struct readyQueue *readyRear = NULL;

readyStart = mallow(sizeof(struct readyQueue) * 1);
readyRear = mallow(sizeof(struct readyQueue) * 1);

我想设置readyStart-＆gt; CPU = -1，readyRead-＆gt; CPU = -1，CPUchoose-＆gt; CPU = -1默认情况下，这意味着我是否声明了新的readyQueue结构

struct readyQueue *CPUchoose = NULL;
CPUchoose = mallow(sizeof(struct readyQueue) * 1);

然后CPUchoose-＆gt; CPU也= = -1，我试图像这样去掉readyQueue

 struct readyQueue
    {
        int start;
        int total_CPU_burst;
        int CPU_burst;
        int CPU_bursted;
        int IO_burst;
        int CPU = -1;
        struct readyQueue *next;
    };

但是，当我构建代码时，它会显示错误，任何人都可以帮助我

Answer 1

创建一个函数来执行此操作：

struct readyQueue* create_readyQueue()
{
    struct readyQueue* ret = malloc( sizeof( struct readyQueue ) );
    ret->CPU = -1;
    // ...
    return ret;
}

struct readyQueue* CPUchoose = create_readyQueue();

你必须记住释放内存，所以最好传入一个指向初始化函数的指针。

void init_readyQueue( struct readyQueue* q )
{
   q->CPU = -1;
   // ...
}


struct readyQueue* CPUchoose = malloc( sizeof( struct readyQueue ) );
init_readyQueue( CPUchoose );
// clearer that you are responsible for freeing the memory since you allocate it.

Answer 2

你可以这样做：

struct readyQueue_s
{
   int start;
   int total_CPU_burst;
   int CPU_burst;
   int CPU_bursted;
   int IO_burst;
   int CPU;
   struct readyQueue_s *next;
}; 

struct readyQueue_s readyQueueDefault = {0, 0, 0, 0, 0, -1, NULL};    

int main(void) 
{
  struct readyQueue_s foo;

  foo = readyQueueDefault;
}

详细了解initialization of structures and unions。

在C中设置struct属性的默认值

2 个答案: