//例题9.1//
#include<stdio.h>
int main()
{struct Student
  {long int num;    //定义长整形num// 
  char name[20];    //定义字符数组name，记住：当没有初始化时，字符数组中数不能空// 
  char sex;     
  char addr[20];   
  }a={10101,"Li Lin",‘M‘,"123 Beijing Road"};      //给定义的数都初始化，注意：字符初始化要有单引号，字符串初始化要有双引号//
  printf("NO.:%ld\nname:%s\nsex:%c\naddress:%s\n",a.num,a.name,a.sex,a.addr);   //输出的变量要对应相应的格式符// 
  return 0;
}

//例题9.2//
#include<stdio.h>
int main()
{struct student
	{  int num;               
	   char name[20];         
	   float score;
	}student1,student2;
	scanf("%d%s%f",&student1.num,&student1.name,&student1.score);       //输入学生1,2的各项值，再输入中一定得加&// 
	scanf("%d%s%f",&student2.num,&student2.name,&student2.score);
	printf("The higher score is:\n");
	if(student1.score>student2.score)                                    //用双重if语句来判断学生们的大小比较// 
	   printf("%d  %s  %6.2f\n",student1.num,student1.name,student1.score);
	else if(student1.score<student2.score)   
	   printf("%d  %s  %6.2f\n",student2.num,student2.name,student2.score);
	else
	{  printf("%d  %s  %6.2f\n",student1.num,student1.name,student1.score);
	   printf("%d  %s  %6.2f\n",student2.num,student2.name,student2.score);
	   }   
    return 0;
}

//例题9.3//
#include<string.h>
#include<stdio.h>
struct person
{char name[20];
 int count;
}leader[3]={"Li",0,"Zhang",0,"Sun",0};
int main()
{int i,j;
 char leader_name[20];
 for(i=1;i<=10;i++)
    {scanf("%s",leader_name);
       for(j=0;j<3;j++)                                                  //用包含for循环选出投票数// 
         if(strcmp(leader_name,leader[j].name)==0)leader[j].count++;
	}
    printf("\nResult:\n");
    for(i=0;i<3;i++)
         printf("%5s:%d\n",leader[i].name,leader[i].count);
   return 0;      
}

//例题9.4//
#include<stdio.h>
struct Student 
{  int num;
   char name[20];
   float score;
};
int main() 
{struct Student stu[5]={{10101,"Zhang",78},{10103,"Wang",98.5},{10106,"Li",86}, {10108,"Ling",73.5},{10110,"Sun",100}};  
 struct Student temp;  
 const int n=5;  
 int i,j,k;  
 printf("The order is:\n");  
 for(i=0;i<n-1;i++)  
     {k=i;   
      for(j=i+1;j<n;j++)
	     if(stu[j].score>stu[k].score) 
		 k=j;
		 temp=stu[k]; 
		 stu[k]=stu[i];
	     stu[i]=temp;
	 }   
	 for(i=0;i<n;i++)   
	      printf("%6d %8s %6.2f\n",stu[i].num,stu[i].name,stu[i].score);
 printf("\n"); 
 return 0; 
}

//例题9.5//
#include<stdio.h>
#include<string.h> 
int main() 
{struct Student  
    {long num;
	 char name[20];
	 char sex; 
	 float score; 
	};struct Student stu_1;
	  struct Student *p; 
	  p=&stu_1; 
	  stu_1.num=10101; 
	  strcpy(stu_1.name,"Li Lin"); 
	  stu_1.sex=‘M‘;  
	  stu_1.score=89.5;  
	  printf("No.:%ld\nname:%s\nsex:%c\nscore:%5.1f\n",stu_1.num,stu_1.name,stu_1.sex,stu_1.score);  
	  printf("\n");  
	  printf("No.:%ld\nname:%s\nsex:%c\nscore:%5.1f\n",(*p).num,(*p).name,(*p).sex,(*p).score);  
  return 0; 
} /

//例题9.6//
#include<stdio.h> 
struct Student 
{int num;  
 char name[20]; 
 char sex;
 int age; 
};struct Student stu[3]={{10101,"Li Lin",‘M‘,18},{10102,"Zhang Fang",‘M‘,19},{10104,"Wang Min",‘F‘,20}}; 
int main() 
{struct Student *p;  
 printf("No.    Name                sex age\n"); 
 for(p=stu;p<stu+3;p++) 
 printf("%5d %-20s %2c %4d\n",p->num,p->name,p->sex,p->age);
 return 0; 
}

//例题9.7//
#include<stdio.h>
#define N 3 
struct Student 
{int num;
 char name[20]; 
 float score[3]; 
 float aver; 
}; 
int main() 
{void input(struct Student stu[]); 
 struct Student max(struct Student stu[]);
 void print(struct Student stud);  
 struct Student stu[N],*p=stu;  
 input(p);  
 print(max(p));  
 return 0; 
} 
void input(struct Student stu[])
{int i;
 printf("请输入各学生的信息：学号、姓名、三门课成绩：\n");
 for(i=0;i<N;i++) 
     {scanf("%d %s %f %f %f",&stu[i].num,&stu[i].name,&stu[i].score[0],&stu[i].score[1],&stu[i].score[2]);
	  stu[i].aver=(stu[i].score[0]+stu[i].score[1]+stu[i].score[2])/3.0;
	 } 
}  
struct Student max(struct Student stu[])
{int i,m=0;
 for(i=0;i<N;i++)
     if(stu[i].aver>stu[m].aver)m=i;
	 return stu[m]; 
}
void print(struct Student stud) 
{printf("\n成绩最高的学生是:\n");  
 printf("学号:%d\n姓名：%s\n三门成绩:%5.1f,%5.1f,%5.1f\n平均成绩:%6.2f\n",stud.num,stud.name,stud.score[0],stud.score[1],stud.score[2],stud.aver);
}