C程序设计(第五版 谭浩强著)再学习第九章

建立一个结构体类型。



定义结构体类型变量。




结构体变量的初始化和引用。
例题9-1

方法1

#include 
struct student
{
	long int number;
	char name[20];
	char sex;
	char addr[20];
}student1 = {10101,"Li Lin",'M',"123 Beijing Road"};
int main(void)
{
	printf("number=%ld,  name=%s,  sex=%c,  address=%s", student1.number, student1.name, student1.sex, student1.addr);
	return 0;
}

方法2

#include 
struct student
{
	long int number;
	char name[20];
	char sex;
	char addr[20];
};
int main(void)
{
	struct student student1= { 10101,"Li Lin",'M',"123 Beijing Road" };
	printf("number=%ld,  name=%s,  sex=%c,  address=%s", student1.number, student1.name, student1.sex, student1.addr);
	return 0;
}

方法3

#include 
struct student
{
	long int number;
	char name[20];
	char sex;
	char addr[20];
}student1;
int main(void)
{
	student1.number = 10101;
	//stduent1.name = "Li Lin";//程序会报错 error C2106: “=”: 左操作数必须为左值
	student1.sex = 'M';
	//stduent1.addr = "123 Beijing Road";//程序会报错
	scanf("%s%s", student1.name, student1.addr);
	printf("number=%ld,  name=%s,  sex=%c,  address=%s", student1.number, student1.name, student1.sex, student1.addr);
	return 0;
}

例题9-2

#include 

struct student
{
	long int num;
	char name[20];
	int grade;
}student1, student2;
int main(void)
{
	printf("please type two student number,name,grade:\n");
	scanf("%ld%s%d", &student1.num, student1.name,&student1.grade);
	scanf("%ld%s%d", &student2.num, student2.name, &student2.grade);
	if (student1.grade > student2.grade)
		printf("num=%ld,name=%s,grade=%d", student1.num, student1.name, student1.grade);
	else
		printf("num=%ld,name=%s,grade=%d", student2.num, student2.name, student2.grade);
	return 0;
}

例题9-3

#include 
struct Person
{
	char name[20];
	int count;
};
int voter_num = 10;
char name[20];
int string_compare(char* a, char* b);
int main(void)
{
	struct Person a[3] = { {"Li",0},{"Zhang",0} ,{"Sun",0} };
	for (int i = 0; i < voter_num; i++)
	{
		scanf("%s", name);
		for (int j = 0; j < 3; j++)
			if (string_compare(name, a[j].name)==1)
				a[j].count++;
	}
	for (int j = 0; j < 3; j++)
		printf("%s=%d\n", a[j].name, a[j].count);
	return 0;
}

int string_compare(char *a, char *b)
{
	int i = 0;
	int flag = 0;
	while (*(a + i) != '\0')
	{
		if (*(a + i) == *(b + i))
			flag = 1;
		else
		{
			flag = 0;
			break; //只要有一个不满足就退出
		}
		i++;
	};
	return flag;
}

例题9-4

#include 
struct message
{	
	long int num;
	char name[20];
	float grade;
};
int main(void)
{
	struct message student[5] = { { 10101,"Zhang",78   },\
								  { 10103,"Wang ",98.5 },\
								  { 10106,"Li   ",86   },\
								  { 10108,"Ling ",73.5 },\
								  { 10110,"Sun  ",100  } };
	struct message temp;
	for (int i = 0; i < 4; i++)
	{
		for (int j = 0; j < 4 - i; j++)
			if (student[j].grade < student[j + 1].grade)
			{
				temp = student[j];
				student[j] = student[j + 1];
				student[j + 1] = temp;
			}
	}
	for (int i = 0; i < 5; i++)
		printf("num=%ld,name=%s,grade=%f\n", student[i].num, student[i].name, student[i].grade);
	return 0;
}

例题9-5

#include 
struct Student
{
	long int num;
	char name[20];
	char sex;
	int score;
};

int main(void)
{
	struct Student student1 = {10101,"Xiaoming",'M',98};
	struct Student *p;
	p = &student1;
	printf("number=%ld,  name=%s,  sex=%c,  address=%d\n", student1.num, student1.name, student1.sex, student1.score);
	printf("number=%ld,  name=%s,  sex=%c,  address=%d\n", (*p).num, (*p).name, (*p).sex, (*p).score);
	return 0;
}

例题9-6

#include 
struct message
{
	long int num;
	char name[20];
	float grade;
};
int main(void)
{
	struct message student[3] = { { 10101,"Zhang",78   },\
								  { 10103,"Wang ",98.5 },\
								  { 10106,"Li   ",86   } };
	struct message* p;
	p = student;
	printf("Method 1:\n");
	for(int i = 0;i<3;i++)
		printf("num=%ld,name=%s,grade=%f\n", student[i].num, student[i].name, student[i].grade);
	printf("Method 2:\n");
	for (int i = 0; i < 3; i++)
		printf("num=%ld,name=%s,grade=%f\n", (*(p + i)).num, (*(p + i)).name, (*(p + i)).grade);
	printf("Method 2:\n");
	for (int i = 0; i < 3; i++)
		printf("num=%ld,name=%s,grade=%f\n", (p + i)->num, (p + i)->name, (p + i)->grade);
	return 0;
}

例题9-7

#define _CRT_SECURE_NO_WARNINGS
#include 
#define N 3

struct message
{
	long int num;
	char name[20];
	float grade[3];
	float average;
};

struct message student[N];
struct message* p;

void input(struct message a[]);
struct message max(struct message a[]);
void print(struct message a);
int main(void)
{
	p = student;
	input(p);
	print(max(p));
	return 0;
} 

void input(struct message a[])
{
	printf("please type number,name,grade\n");
	for (int i = 0; i < N; i++)
	{
		scanf("%ld %s %f %f %f", \
			& a[i].num, \
			a[i].name, \
			& a[i].grade[0], \
			& a[i].grade[1], \
			& a[i].grade[2]);	
		a[i].average = (a[i].grade[0] + a[i].grade[1] + a[i].grade[2]) / 3.0f;
	}
}

struct message max(struct message a[])
{
	float max_value = a[0].average;
	int m = 0;
	for (int i = 0; i < N; i++)
	{
		if (a[i].average > max_value)
		{
			max_value = a[i].average;
			m = i;
		}
	}
	return a[m];
}

void print(struct message a)
{
	printf("number=%ld,name=%s,grade1=%0.2f,grade2=%0.2f,grade3=%0.2f,average=%0.2f", a.num, a.name, a.grade[0], a.grade[1], a.grade[2], a.average);
}

输入的内容如下

10101 Li 78 89 98
10103 Wang 98.5 87 69
10106 Sun 88 76.5 89

#include 

struct Student
{
	int num;
	float socre;
	struct Student* next;//指针
};

int main(void)
{
	struct Student a, b, c, * head, * p;
	a.num = 10101; a.socre = 89.5;
	b.num = 10103; b.socre = 90;
	c.num = 10107; c.socre = 85;
	head = &a;
	a.next = &b;
	b.next = &c;
	c.next = NULL;
	p = head;
	do
	{
		printf("%ld %5.1f\n", p->num, p->socre);
		p = p->next;
	} while (p != NULL);
	return 0;
}