结构体

1.访问结构字段，点表示法，用  .   运算符

2.typedef为结构创建别名，用typedef定义结构时可以省略结构名

例如：

typedef struct cell_phone
{
    int cell_no;
    const char *wallpaper;
    float minutes_of_charge;
}phone;// struct cell_phone是结构名，phone是类型名（别名），有了别名可以不写结构名
phone p = {5557879,"s.png",1.35}; 

3.想把结构传给函数并在函数中更新他的值，需要使用结构指针

4.(*t).age = t->age 才有效

   *t.age = *(t.age) 并无实际意义

练习一：结构体

#include <stdio.h>

struct exercise
{
    const char *description;
    float duration;
};
struct meal
{
    const char *ingredient;
    float weight;
};
struct preferences
{
    struct meal food;//结构体中的结构 struct meal 是新结构体，food是名称
    struct exercise exercise;
};


struct fish
{
    const char *name;//注意定义字符串的两种方法
    const char species[20];
    int teeth;
    int age;
    struct preferences care;
};//定义结构体后记得加分号

void catalog(struct fish f)
{
    printf("%s is a %s with %i teeth. He is %i\n",f.name,f.species,f.teeth,f.age);
}
void label(struct fish f)
{
    printf("Name:%s\n Species:%s\n %i years old,%i teeth\n",f.name,f.species,f.teeth,f.age);
    printf("Feed with %2.2f lbs of %s and allow to %s for %2.2f hours\n",
        f.care.food.weight,f.care.food.ingredient,
        f.care.exercise.description,f.care.exercise.duration);
}

int main()
{
    struct fish snappy = {"Snappy","Piranha",69,4,{{"meat",0.2},{"swim in the jacuzzi",7.5}} };
    catalog(snappy);
    label(snappy);
    return 0;
}

练习二：typedef的运用

#include <stdio.h>

typedef struct
{
    float tank_capacity;
    int tank_psi;
    const char *suit_material;
}equipment;

typedef struct scuba
{
    const char *name;
    equipment kit;
}driver;

void badge(driver d)
{
    printf("Name:%s Tank:%2.2f(%i) Suit:%s\n",d.name,d.kit.tank_capacity,d.kit.tank_psi,d.kit.suit_material);
}

int main()
{
    driver randy = {"Randy",{5.5,3500,"Neoprene"}};
    badge(randy);
    return 0;
}

练习三：

#include <stdio.h>

typedef struct
{
    const char *name;
    const char *special;
    int age;
}turtle;

void happy_birthday(turtle *t)
{
    (*t).age = (*t).age + 1;//注意一定要加（）,(*t).age = t -> age
    printf("Happy birthday %s! You are now %i years old!\n",(*t).name,(*t).age);
}
int main()
{
    turtle myrtle = {"Myrtle","Leatherback sea turtle",99};
    happy_birthday(&myrtle);
    printf("%s's age is now %i\n",myrtle.name,myrtle.age);
    return 0;
}