学点 C 语言(25): 数据类型 - 结构数组与结构指针

1. 结构数组:

---

#include <stdio.h>

int main(void)
{
    struct Rec {int x,y;};

    struct Rec rs[10];
    
    size_t i;
    for (i = 0; i < sizeof rs/sizeof rs[0]; i++) {
        rs[i].x = i;
        rs[i].y = i * 2;    
    }

    for (i = 0; i < sizeof rs/sizeof rs[0]; i++) {
        printf("%d, %d\n", rs[i].x, rs[i].y);    
    }
    
    getchar();
    return 0;
}

#include <stdio.h>

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    } rs[3] = {
                {"AAA", 11},
                {"BBB", 22},
                {"CCC", 22}
              };

 
    size_t i;

    for (i = 0; i < sizeof rs/sizeof rs[0]; i++) {
        printf("%s, %d\n", rs[i].name, rs[i].age);    
    }
    
    getchar();
    return 0;
}

2. 结构指针指向已存在的结构数组:

---

#include <stdio.h>

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    } rs[3] = {
                {"AAA", 11},
                {"BBB", 22},
                {"CCC", 22}
              };

    struct Rec *p = rs;
 
    printf("%s, %d\n", p->name, p->age);
    printf("%s, %d\n", (p+1)->name, (p+1)->age);
    printf("%s, %d\n", (p+2)->name, (p+2)->age);
    
    getchar();
    return 0;
}

3. 结构指针(单个结构):

---

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

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    };

    struct Rec *p = NULL;
 
    p = (struct Rec *)malloc(sizeof(struct Rec));

    stpcpy(p->name, "ABC");
    p->age = 99;

    printf("%s, %d\n", p->name, p->age);
    printf("%s, %d\n", (*p).name, (*p).age);

    free(p);     
    
    getchar();
    return 0;
}

4. 结构指针(多个结构):

---

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    struct Rec {
        int x;
        int y;
    } *p;

    size_t i, count = 10;

    p = (struct Rec *)malloc(sizeof(struct Rec)*count);

    for (i = 0; i < count; i++) {
        (p+i)->x = i;
        (p+i)->y = i * i;
    }

    for (i = 0; i < count; i++) {
        printf("%d, %d\n", (p+i)->x, (p+i)->y);    
    }

    free(p);     
    
    getchar();
    return 0;
}

5. 连续的多个结构不就是结构数组了吗?(同上例)

---

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    struct Rec {
        int x;
        int y;
    } *p;

    size_t i, count = 10;

    p = (struct Rec *)malloc(sizeof(struct Rec)*count);

    for (i = 0; i < count; i++) {
        p[i].x = i;
        p[i].y = i * i;
    }

    for (i = 0; i < count; i++) {
        printf("%d, %d\n", p[i].x, p[i].y);    
    }

    free(p);     
    
    getchar();
    return 0;
}