C: البنى — المتقدمة

struct Point make_point(int x, int y) {
    struct Point p = {x, y};
    return p;
}

int main(void) {
    struct Point pt = make_point(3, 4);
    printf("(%d, %d)\n", pt.x, pt.y);
    return 0;
}

void fill_student(struct Student *s, const char *name, int age, float score) {
    strncpy(s->name, name, 19);
    s->name[19] = '\0';
    s->age = age;
    s->score = score;
}

int main(void) {
    struct Student stu;
    fill_student(&stu, "Zhang", 20, 88.5);
    return 0;
}

void print_student(const struct Student *s) {
    printf("%s %d %.1f\n", s->name, s->age, s->score);
}

typedef struct {
    char name[20];
    int age;
    float score;
} Student;

Student s1 = {"Zhang", 20, 89.5};
Student *ps = &s1;

typedef struct Node {
    int data;
    struct Node *next;
} Node, *NodePtr;

Node n1 = {10, NULL};
NodePtr head = &n1;

typedef unsigned char Byte;
typedef int (*Comparator)(const void *, const void *);

Byte flag = 0xFF;
Comparator cmp = my_compare;

#include <stdio.h>
#include <string.h>

typedef struct {
    char title[50];
    int pages;
    float price;
} Book;

Book create_book(const char *title, int pages, float price) {
    Book b;
    strncpy(b.title, title, 49);
    b.title[49] = '\0';
    b.pages = pages;
    b.price = price;
    return b;
}

void discount(Book *b, float rate) {
    b->price *= rate;
}

void print_book(const Book *b) {
    printf("<%s> %d pages $%.2f\n", b->title, b->pages, b->price);
}

int main(void) {
    Book b1 = create_book("C Programming", 320, 59.0);
    print_book(&b1);
    discount(&b1, 0.8);
    print_book(&b1);
    return 0;
}

<C Programming> 320 pages $59.00
<C Programming> 320 pages $47.20

struct Align1 {
    char a;
    int b;
    char c;
};

struct Align2 {
    char a;
    char c;
    int b;
};

printf("%zu\n", sizeof(struct Align1));
printf("%zu\n", sizeof(struct Align2));

12
8

#pragma pack(push, 1)
struct Packed {
    char a;
    int b;
    char c;
};
#pragma pack(pop)

printf("%zu\n", sizeof(struct Packed));

6

struct Flags {
    unsigned int ready : 1;
    unsigned int error : 1;
    unsigned int mode  : 3;
    unsigned int       : 0;
    unsigned int count : 12;
};

struct Flags f = {1, 0, 5, 1024};
printf("ready=%u error=%u mode=%u count=%u\n", f.ready, f.error, f.mode, f.count);
printf("Struct size: %zu\n", sizeof(f));

ready=1 error=0 mode=5 count=1024
Struct size: 8

typedef struct {
    int len;
    int data[];
} IntVec;

int n = 5;
IntVec *v = (IntVec *)malloc(sizeof(IntVec) + sizeof(int) * n);
v->len = n;
for (int i = 0; i < n; i++) {
    v->data[i] = i * 100;
}
for (int i = 0; i < v->len; i++) {
    printf("%d ", v->data[i]);
}
free(v);

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