typedef

0. 理解

• 作用：给一个 已知数据类型 起别名

1. 基本数据类型

typedef int Integer;
int main() {
  Integer num = 100;
  printf("%i\n", num);
  return 0;
}

2. 指针

typedef char *String;
int main() {
  String name = "王小熊";
  printf("name = %s\n", name);
  return 0;
}

int sum(int v1, int v2) {
  return v1 + v2;
}
int minus(int v1, int v2) {
  return v1 - v2;
}
typedef int(*functionPotinter)(int , int);
int main() {
  functionPotinter sumP = sum;
  printf("sum = %i\n", sumP(20, 10));
  functionPotinter minusP = minus;
  printf("minus = %i\n", minusP(20, 10));
  return 0;
}

3. 结构体

struct Person {
  char *name;
  int age;
  double height;
};
typedef struct Person SPerson;
int main() {
  SPerson sp = {"秦子阳", 18, 1.88};
  printf("%s\n", sp.name);
  return 0;
}

typedef struct Person {
  char *name;
  int age;
  double height;
} Sperson;
int main() {
  Sperson sp = {"秦子阳", 18, 1.88};
  printf("%s\n", sp.name);
  return 0;
}

typedef struct {
  char *name;
  int age;
  double height;
} Sperson;
int main() {
  Sperson sp = {"秦子阳", 18, 1.88};
  printf("%s\n", sp.name);
  return 0;
}

4. 枚举

enum Gender {
  kGenderMale,
  kGenderFemale
};
typedef enum Gender SEX;
int main() {
  SEX sex = kGenderFemale;
  printf("%i\n", sex);
  return 0;
}

typedef enum Gender {
  kGenderMale,
  kGenderFemale
} SEX;
int main() {
  SEX sex = kGenderFemale;
  printf("%i\n", sex);
  return 0;
}

typedef enum {
  kGenderMale,
  kGenderFemale
} SEX;
int main() {
  SEX sex = kGenderFemale;
  printf("%i\n", sex);
  return 0;
}