C语言学习之标识符的使用详解

int age;
float average_score;
char first_name[50];
void print_hello();

int student_age;
float average_score;
char first_name[50];

int calculate_sum(int a, int b);
float calculate_average(float *array, int size);

#define PI 3.14159
const int MAX_SIZE = 1024;

struct StudentInfo {
    char name[50];
    int age;
};
uNIOn Color {
    int value;
    struct {
        unsigned char red;
        unsigned char green;
        unsigned char blue;
    } rgb;
};

enum Color {
    RED,
    GREEN,
    BLUE
};
enum WeekDay {
    MONDAY,
    TUESDAY,
    WEDNESDAY,
    THURSDAY,
    FRIDAY,
    SATURDAY,
    SUNDAY
};

#include <stdio.h>
// 定义一个结构体
struct StudentInfo {
    char name[50];
    int age;
};
// 定义一个函数
void print_student_info(struct StudentInfo student) {
    printf("Name: %s\n", student.name);
    printf("Age: %d\n", student.age);
}
// 定义一个常量
#define MAX_STUDENT_NUM 100
int main() {
    // 定义一个变量
    int student_num;
    // 定义一个结构体类型的变量
    struct StudentInfo student1 = {"Alice", 18};
    // 调用函数
    print_student_info(student1);
    // 修改结构体类型的变量
    student1.age = 19;
    // 输出变量值和常量值
    student_num = 10;
    printf("Student num: %d\n", student_num);
    printf("Max student num: %d\n", MAX_STUDENT_NUM);
    return 0;
}