结构体（二）

0. 指针和结构体

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• 概念：通过 指针 保存 结构体变量地址

  struct Person {
    char *name;
    int age;
    double height;
  };
  struct Person sp = {"wxx", 18, 2.00};
  struct Person *sip = NULL;
  sip = &sp;
  

• 操作

  struct Person {
  char *name;
  int age;
  double height;
  };
  struct Person sp = {"wxx", 18, 2.00};
  struct Person *sip = NULL;
  sip = &sp;
  
  (*sip).name = "qtt";
  (*sip). age = 18;
  (*sip). height = 1.75;
  printf("name = %s, age = %i, height = %lf\n", (*sip).name, (*sip). age, (*sip). height);
  
  sip->name = "xdy";
  sip->age = 1;
  sip->height = 0.75;
  printf("name = %s, age = %i, height = %lf\n", sip->name,  sip->age, sip->height);
  

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1. 结构体数组

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• 概念：数组元素 为 结构体值

  struct Department {
    char *name;
    int count;
    double kpi;
  };
  struct Department departments[3] = {
  
    {"iOS", 10, 100.0},
    {"andorid", 10, 88.0},
    {"php", 100, 66.0}
  
  };
  departments[0].name = "秦子阳";
  departments[0].count = 1000;
  departments[0].kpi = 10000.0;
  printf("name = %s, count = %i, kpi = %lf\n", departments[0].name, departments[0].count, departments[0].kpi);
  

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2. 结构体嵌套

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• 概念：结构体属性 又是 一个结构体

  struct Time {
  
    int HH;
    int mm;
    int ss;
  
  };
  
  struct Data {
    
    int year;
    int month;
    int day;
    struct Time time;
    
  };
  
  struct Person {
    
    char *name;
    int age;
    struct Data work;
    
  };
  
  struct Person sp = {
    
    "wxx",
    18,
    {
      2016,
      10,
      10,
      {
        9,
        10,
        8
      }
    }
    
  };
  
  printf("year = %i, month = %i, day = %i\n", sp.work.year, sp.work.month, sp.work.day);
  

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3. 结构体和函数

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• 结构体类型变量 作为 形参，修改形参数据 不能改变 实参数据

  struct Person {
  
  char *name;
  int age;
  double height;
  
  };
  
  void demo(struct Person);
  
  int main(int argc, const char * argv[]) {
  
    struct Person sp = {"wx", 18, 2.00};
  
    demo(sp);
  
    printf("sp.age = %i\n", sp.age);
  
    return 0;
  
  }
  
  void demo(struct Person p) {
  
    p.age = 20;
  
    printf("p.age = %i\n", p.age);
  
  }
  

• 结构体类型指针变量 作为 形参，修改形参数据 会改变 实参数据

  struct Person {
  
  char *name;
  int age;
  double height;
  
  };
  
  void demo(struct Person *);
  
  int main(int argc, const char * argv[]) {
  
    struct Person sp = {"wx", 18, 2.00};
  
    demo(&sp);
  
    printf("sp.age = %i\n", sp.age);
  
    return 0;
  
  }
  
  void demo(struct Person *p) {
  
    p->age = 20;
  
    printf("p.age = %i\n", p->age);
  
  }
  

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