初始化

结构与数组的初始化都要用 {}
例如：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
struct name {
    char first_name[LEN];
    char last_name[LEN];
};

struct student {//结构
    struct name names;//结构
    float grade[NUM];//数组
    float average;
};
struct student score[CSIZE] = {
    {{"Zha", "Yujie"}, {0, 0, 0}, 0},
    {{"Jiang", "Wenjie"}, {0, 0, 0}, 0},
    {{"Liu", "Chengming"}, {0, 0, 0}, 0},
    {{"Pan", "Xiangxiang"}, {0, 0, 0}, 0}

结构数组的传递

C能传递整个结构。
但C不能传递整个数组，可以传递首元素地址，在函数中关联这个数组。

  • 当遇到结构数组时，
    要在函数中用地址关联这个数组，也只能传递结构数组的首元素的地址。
    这个元素就是一个结构。

示例

  1. 数组名 = 数组的首元素地址
    jones = &jones[0]
注意是array of structures
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
/* funds4.c -- passing an array of structures to a function */
#include <stdio.h>
#define FUNDLEN 50
#define N 2

struct funds {
    char   bank[FUNDLEN];
    double bankfund;
    char   save[FUNDLEN];
    double savefund;
};

double sum(const struct funds money[], int n);

int main(void)
{
    struct funds jones[N] = {
        {
            "Garlic-Melon Bank",
            4032.27,
            "Lucky's Savings and Loan",
            8543.94

        },
        {
            "Honest Jack's Bank",
            3620.88,
            "Party Time Savings",
            3802.91
        }
    };
    
    printf("The Joneses have a total of $%.2f.\n",
           sum(jones,N));           //jones = &jones[0]
    
    return 0;
}

double sum(const struct funds money[], int n)
{
    double total;
    int i;
    
    for (i = 0, total = 0; i < n; i++)
        total += money[i].bankfund + money[i].savefund;//money是地址
    
    return(total);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
#include<stdio.h>
#define MON 12
struct year
{
    char * m_name;
    int days;
    int m;
};
int Days(int, struct year *, int *sum);
int main()
{
    struct year month[MON];//结构数组
    char * name[12] = {"Jan", "Feb", "Mar", "Ari", "May",
     "Jun", "Jul", "Aug", "Set", "Oct", "Nov", "Dem"};
    int mon, sum;
    for (int i = 0; i < MON; i++)
    {
        month[i].m_name = name[i];
        if(i % 2 == 0)
            month[i].days = 31;
        else
            month[i].days = 30;
        month[i].m = i + 1;
    }
    month[1].days = 28;//不是闰年
    printf("Enter the month(else to quit): ");
    while(scanf("%d", &mon))
    {
        if(mon <= 12 && mon >= 1)
        {
            sum = 0;
            sum = Days(mon, month, &sum);
            printf("%d\n", sum);
            printf("Enter the month again: ");
        }
        else 
            return (-1);
        
    }
    return 0;
}

int Days(int mon, struct year * month, int *sum)
{
    for (int i = 0; i < mon; i++)
    {
        *sum += month[i].days;
    }
    return *sum;
}
打印班级平均分
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
#include<stdio.h>
#include<string.h>
#define LEN 40
#define CSIZE 4
struct name
{
    char fname[LEN];
    char lname[LEN];
};
struct student
{
    struct name n;
    double grade[3];
    double average;
};
char * s_gets(char * st, int n);
void get_grade(struct student *, char **);
void get_average(struct student *);
void print(struct student *);
int main()
{
    struct student person[CSIZE] = 
    {
        [0] = {"ferry", "chan"},
        [1] = {"faye", "chan"},
        [2] = {"tom", "sion"},
        [3] = {"jim", "sion"}
    };
    char *str[] = {"ferry chan", "faye chan", "tom sion", "jim sion"};
    get_grade(person, str);
    get_average(person);
    print(person);
    printf("The average of class is %lf",
    (person[0].average + person[1].average + person[2].average + person[3].average) / 4);
    return 0;
}

void get_grade(struct student *p, char **str)
{
    int i;
    char fullname[LEN];
    for(int n = 0; n < 4; n++)
    {
        int temp = 0;
        puts("Enter stduent's fullname: ");
        s_gets(fullname, LEN);//读入的时候要是数组类型，如果用指针，会乱指
        
        for(i = 0; i < 4; i++)
        if(strcmp(fullname, str[i]) == 0)
        {
            temp = 1;
            break;
        }
        if(temp)
        {
            for(int j = 0; j < 3; j++)
            {
                printf("Enter your the %dth grade: ", j + 1);
                scanf("%lf", &(p[i].grade[j]));
                getchar();
            }
        }
    }
}

void print(struct student *p)
{
    for(int i = 0; i < 4; i++)
    {
        printf("%s %s's grade is %lf %lf %lf and your average is %lf\n", 
            p[i].n.fname, p[i].n.lname, p[i].grade[0], p[i].grade[1], p[i].grade[2], p[i].average);
    }
}

void get_average(struct student * p)
{
    for(int i = 0; i < 4; i++)
    {
        int sum = 0;
        for(int j = 0; j < 3; j++)
        {
            sum += p[i].grade[j];
        }
        p[i].average = sum / 3;
    }
}

char * s_gets(char * st, int n)
{
    char * find;
    char * ret_val;

    ret_val = fgets(st, n, stdin);
    if (ret_val)
    {
        find = strchr(st, '\n');	//查找换行符
        if (find)
            *find = '\0';			//替换为空字符
        else
            while (getchar() != '\n')
                continue;	//处理多余输入
    }

    return ret_val;
}