结构体

1 结构体及应用

 

 

struct student
{
  int ID;
  char name[20];
  char sex;
  float score;
};
struct student s[4]= {{
    10001,"张三",'M',95
  },
  {10002,"李四",'F',92},
  {10002,"王五",'F',96}
};                //定义了结构体数组stu[4]并对前两个赋值

void f1_1()
{
    //结构体变量实例
    struct student a= {1,"张三1",'M',95};       //定义变量并赋值
    struct student b= {2,"李四1",'F',100};       //不能改变赋值顺序
    struct student c;                              //结构体c未赋初值
    //scanf("%d%s%c%f",&c.ID,c.name,&c.sex,&c.score);//注意c.name前无"&"
    cin>>c.ID>>c.name>>c.sex>>c.score;
    //printf("%d %s %c %f\n",a.ID,a.name,a.sex,a.score);
    cout<<a.ID<<" "<<a.name<<" "<<a.sex<<" "<<a.score<<" "<<endl;
    cout<<b.ID<<" "<<b.name<<" "<<b.sex<<" "<<b.score<<" "<<endl;
    cout<<c.ID<<" "<<c.name<<" "<<c.sex<<" "<<c.score<<" "<<endl;
}
void  f1()
{
    //结构体及其应用 
  //scanf("%d %s %c %f",&s[2].ID,s[2].name,&s[2].sex,&s[2].score);
  cin>>s[3].ID>>s[3].name>>s[3].sex>>s[3].score;
  for(int i=0; i<4; i++)
  {
        //printf("%d %s %c %f\n",s[i].ID,s[i].name,s[i].sex,s[i].score);
        cout<<s[i].ID<<s[i].name<<s[i].sex<<s[i].score<<endl;
  }    
  //return 9;
}

语句scanf("%d%s%c%f",&c.ID,c.name,&c.sex,&c.score)中，c.name的前面没有加取地址符“&”，因为c.name本身就是数组的首地址。
可以看出，结构体内的成员变量可以像普通变量一样进行各种操作。例如：
a.score=b.score;
sum=a.score+b.score;
a.score++;
应该逐个操作结构体内的各变量，不能将各变量作为整体一次操作完，例如输入输出写成cin>>a或者cout<<a都是错误的，应改为:
cin>>a.ID>>a.name>>a.sex>>a.score;
cout<<a.ID<<a.name<<a.sex<<a.score;

2 结构体与指针

void f2()
{
    //结构体与指针
    struct student *p;
    for(p=s; p<s+4; p++) //p为指向结构体的指针，自身加１即指向下一结构体元素
      cout<<p->ID<<p->name<<p->sex<<p->score<<endl;
}
void f21()
{
    //结构体指针变量指向结构体变量
    struct student stu;   //定义结构体变量stu
    struct student *p;    //*p必须和stu一样，均为struct student类型
    p=&stu;               //结构体指针p指向结构体stu
    stu.ID=10001;
    strcpy(stu.name,"苏州1");//无法用"="对字符数组赋值，故用strcpy()
    stu.sex='M';
    stu.score=100;
    cout<<stu.ID<<stu.name<<stu.sex<<stu.score<<endl;
    cout<<(*p).ID<<(*p).name<<(*p).sex<<(*p).score<<endl; 
}

3 选举

#include <string.h> 

struct person
{
  char name[150];
  int count;
} leader[200];

void f2_2()
{
    /*
    选举
    */
  int n,m;
  cin>>n;
  for(int i=0; i<n; i++)
  {
    cin>>leader[i].name;
    leader[i].count=0;
  }
  cin>>m;
  char name[m];
  for(int i=1; i<=m; i++)
  {
    cin>>name;
    for(int j=0; j<n; j++)
      if(strcmp(name,leader[j].name)==0)
        leader[j].count++;
  }
  for(int i=0; i<n; i++)
    cout<<leader[i].name<<" "<<leader[i].count<<endl;
}

4 统计成绩

 

struct student1
{
  int num;
  char name[8];
  int mark[3];
} person1[11];
#include<iomanip>
void f22()
{
    //统计成绩
    freopen("score.in","r",stdin);
    int maxi=0;
    float aver,aver1,max=0,sum=0;
    for(int i=0; i<10; i++)
    {
      cin>>person1[i].num>>person1[i].name;
      cin>>person1[i].mark[0]>>person1[i].mark[1]>>person1[i].mark[2];
      sum+=person1[i].mark[0];
      sum+=person1[i].mark[1];
      sum+=person1[i].mark[2];
      aver1=(float)(person1[i].mark[0]+person1[i].mark[1]+person1[i].mark[2]);
      aver1=aver1/3;
      if(aver1>max)
      {
        max=aver1;
        maxi=i;
      }
    }
    aver=sum/30;
    cout<<setprecision(2)<<fixed<<aver<<endl;
    cout<<person1[maxi].num<<" "<<person1[maxi].name<<" "<<setprecision(2)<<fixed<<max<<endl;    
}

5 生日

 

struct Stu
{
  string s;
  int y,m,d;
} stu[200];
#include<algorithm> 
void exchange(int i,int j)
{
  swap(stu[i].s,stu[j].s);
  swap(stu[i].y,stu[j].y);
  swap(stu[i].m,stu[j].m);
  swap(stu[i].d,stu[j].d);
}

void f23()
{
    //生日
     freopen("birthday.in","r",stdin);
    int n;
    //scanf("%d",&n);
    cin>>n;    
  for(int i=1; i<=n; ++i)
    cin>>stu[i].s>>stu[i].y>>stu[i].m>>stu[i].d;
  for(int i=1; i<n; ++i)
    for(int j=i+1; j<=n; ++j)
      if(stu[i].y>stu[j].y)
        exchange(i,j);
      else if(stu[i].y==stu[j].y)
        if(stu[i].m>stu[j].m)
          exchange(i,j);
        else if(stu[i].m==stu[j].m)
          if(stu[i].d>=stu[j].d)
            exchange(i,j);
  for(int i=1; i<=n; ++i)
    cout<<stu[i].s<<endl;
}