Question

这一定是一个非常简单的问题，我有一个结构中有四个元素，一个结构变量被初始化为一个数组，现在的问题是我可以访问数组的第一行但我不知道如何访问剩余的行...请指导我！

  //structure is defined as follows      
  typedef struct{
        char first_name[100];
        char second_name[100];
        int x_position;
        int y_position;       
    } names;   

 int main(void)
 {
   int i=0;    
   //here i have initilized structure variable   
  names my_data[] = {
                {"First", "Row",  20, 12},
                {"Second", "Row", 55, 30},
                {"Third",  "Row", 80, 47},
                {"Fourth", "Row", 27, 34}
              }; 
    //trying to acess the diffrent row elements ....but dont know how??
    for(i=0; i<=3; i++)
    {
        printf("%s\n",my_data->first_name);
        printf("%s\n",my_data->second_name);
        printf("%d\n",my_data->x_position);
        printf("%d\n",my_data->y_position);
    }   
    system("PAUSE");    
    return 0;
   }

Answer 1

循环纠正：

 printf("%s\n", my_data[i].first_name);

注意：[]数组下标运算符的precedence高于.成员选择，通过对象名称运算符，因此您不需要()括号。

或

 printf("%s\n",(my_data + i)->first_name);

第二，+加运算符的优先级较低，因此我们需要括号来覆盖优先级。

Answer 2

您需要放置i： -

  printf("%s\n",my_data[i].first_name);

更改了代码： -

//structure is defined as follows

  typedef struct{
        char first_name[100];
        char second_name[100];
        int x_position;
        int y_position;

        }names;


 int main(void)
 {
     int i=0;

   //here i have initilized structure variable

  names my_data[] = {         {"First", "Row",  20, 12},
                              {"Second", "Row", 55, 30},
                              {"Third",  "Row", 80, 47},
                              {"Fourth", "Row", 27, 34}
                                             }; 
    //trying to acess the diffrent row elements ....but dont know how??
    for(i=0; i<=3; i++)
    {
    printf("%s\n",my_data[i]->first_name);
    printf("%s\n",my_data[i]->second_name);
    printf("%d\n",my_data[i]->x_position);
    printf("%d\n",my_data[i]->y_position);
    }

   system("PAUSE");

    return 0;
   }

Answer 3

//structure is defined as follows

#include <stdio.h>

  typedef struct{
        char first_name[100];
        char second_name[100];
        int x_position;
        int y_position;

        }names;


 int main(void)
 {
     int i=0;

   //here i have initilized structure variable

  names my_data[] = {         {"First", "Row",  20, 12},
                              {"Second", "Row", 55, 30},
                              {"Third",  "Row", 80, 47},
                              {"Fourth", "Row", 27, 34}
                                             }; 
    //trying to acess the diffrent row elements ....but dont know how??
    for(i=0; i<=3; i++)
    {
    printf("%s\n",my_data[i].first_name);
    printf("%s\n",my_data[i].second_name);
    printf("%d\n",my_data[i].x_position);
    printf("%d\n",my_data[i].y_position);
    }


    return 0;
   }

你应该索引数组中所需的项目;在您的示例中，您使用my_data作为指向my_data [0]

的指针

Answer 4

有不同的方式。您可以使用索引变量来访问此处其他人提到的字段，也可以使用指针。您可以在数组中添加一个额外的空字段，以将其标记为数据结尾：

names my_data[] = {
    {"First", "Row",  20, 12},
    {"Second", "Row", 55, 30},
    {"Third",  "Row", 80, 47},
    {"Fourth", "Row", 27, 34}
    {NULL, NULL, 0, 0}
}; 

names* my_data_ptr = my_data;
while (my_data_ptr->first_name) {
    printf("%s\n",my_data_ptr->first_name);
    printf("%s\n",my_data_ptr->second_name);
    printf("%d\n",my_data_ptr->x_position);
    printf("%d\n",my_data_ptr->y_position);
    my_data_ptr++;
}

优点是你不必提前知道阵列的大小。

如何访问数组中结构的成员？

4 个答案: