《C语言程序设计》第4版 何钦铭、颜晖主编 课后习题答案 第9章 课后习题

P226页

练习9-1,9-2,9-3

#include//练习9-1 
struct plural{
	double real;
	double imag;
};
int main(void)
{
	struct plural number;
	printf("实部，虚部：");
	scanf("%.2lf%.2lf",&number.real,&number.imag);
//	printf("%lf",number.imag);
//	printf("此复数为；%.2lf+%.2lfi",number.real,number.imag);
	
	return 0;
}

#include//练习9-2 
struct birthday{
	int year;
	int month;
	int day;
};
struct student
{
	int num;
	char name[10];
	int math,english,computer;
	struct birthday bir;
	double average;
};
int main(void)
{
	struct student s,max;
	int n,i,j;
	
	printf("Enter n:");
	scanf("%d",&n);
	for(i=0;imax.average)//成员比较 
		{
			max=s;//整体赋值 
		}
	} 
	printf("学号t姓名t数学t英语t计算机t平均分t年—月—日n");
	printf("%dt%st%dt%dt%dt%.2lft%2d-%2d-%2dn",max.num,max.name,max.math,max.english,max.computer,max.average,max.bir.year,max.bir.month,max.bir.day);
	
	return 0;
}

#include//练习9-3 
#define N 50
struct student
{
	int num;
	char name[10];
	int math,english,computer;
	double average;
};
int main(void)
{
	struct student s[N];
	int n,i,j;
	
	printf("Enter n:");
	scanf("%d",&n);
	for(i=0;i 
P228页
 
练习9-4,9-5
 
#include//练习9-4 
struct student{
	int num;
	char name[10];
	int math,english,computer;
};
int main(void)
{
	struct student stu[5]={{101,"zhang",86,98,88},{103,"li",65,67,68},{106,"wang",55,54,58},{102,"qian",65,62,64},{109,"sun",86,49,58}};
	int i; 
	
	printf("学号t姓名t数学t英语t计算机n");
	for(i=0;i<5;i++)
	{
		printf("%dt%st%dt%dt%dn",stu[i].num,stu[i].name,stu[i].math,stu[i].english,stu[i].computer);
	}
	
	return 0;
}
 
#include//练习9-5 
struct student
{
	int num;
	char name[10];
	int math,english,computer;
	double average;
};
int main(void)
{
	struct student s[10];
	int i,max=0,min=0;
	
	for(i=0;i<10;i++)
	{
		printf("请输入学号；");
		scanf("%d",&s[i].num);
		printf("请输入姓名；");
		scanf("%s",s[i].name);
		printf("请输入数学，英语，计算机成绩：");
		scanf("%d%d%d",&s[i].math,&s[i].english,&s[i].computer);
		s[i].average=(s[i].computer+s[i].english+s[i].math)/3.0;
		if(s[i].average>s[max].average){
			max=i;
		} else if(s[i].average 
P232页
 
练习9-6,9-7
 
#include//练习9-6 
struct student
{
	int num;
	char name[10];
	int math,english,computer;
	double average;
};
int main(void)
{
	struct student stu,*p;
	p=&stu;
	printf("请输入学号；");
	scanf("%d",&(*p).num);
	printf("请输入姓名；");
	scanf("%s",(*p).name);
	printf("请输入数学，英语，计算机成绩：");
	scanf("%d%d%d",&(*p).math,&(*p).english,&(*p).computer);
	(*p).average=((*p).computer+(*p).english+(*p).math)/3.0;
	printf("学号t姓名t数学t英语t计算机t平均分n");
	printf("%dt%st%dt%dt%dt%.2lfn",p->num,p->name,p->math,p->english,p->computer,p->average);

	return 0;
}
 
#include//练习9-7 
#define N 50
struct student
{
	int num;
	char name[10];
	int math,english,computer;
	double average;
};
void alter(struct student s[],int n,int num,int math)
{
	int i,k;
	char ch;
	for(i=0;i