结构体 _0215

1.#结构体变量的定义，赋值
#include <stdio.h>

struct student
{
    int id;
    char name[32];
    int score;
};

//全局变量
struct student stu1={1,"Jack",100};
struct student stu2={2,"Tom",89};

int main(int argc, const char *argv[])
{
    //局部变量
    struct student stu3;
    memset(&stu3,0,sizeof(stu3));
    //将stu3中的内容置0
    //共12个字节,4字节对齐。数据线32根，4字节对齐存取，填充字节时存取方便
    //对齐方式由编译器决定,#prakgma pack(1)  设置1字节对齐
    //#prakgma pack() 恢复默认设置
    return 0;
}
2.#structl类型可以整体赋值
#include <stdio.h>

struct student
{
    int id;
    char name[32];
    int score;
};

int main(int argc, const char *argv[])
{
    struct student stu1={1,"Jack",100};
    struct student stu2;
    stu2=stu1;  //都为struct类型变量，struct类型可以整体赋值，实现整体复制。
    return 0;
}
3.#函数的返回值为struct类型
#include <stdio.h>

struct student
{
    int id;
    char name[32];
    int score;
}stu1={1,"Jack",100};

struct student print_stu(struct student stu)
{
    printf("id=%d name=%s score=%d\n",stu.id+1,stu.name,stu.score);
    return stu;
}

int main(int argc, const char *argv[])
{
    struct student a;
    a=print_stu(stu1);
    return 0;
}
4.#用struct类型实现求一个元素个数为10的数组的最大值，平均值和数组中偶数的个数
#include <stdio.h>

struct stru
{
    int max;
    float avg;
    int evenn;
};

struct stru func(int *a,int n)
{
    int i;
    struct stru arr={a[0],0.0,0};
    float sum=0.0;
    for (i = 0; i < n; i++)
    {
        if(a[i]>arr.max)
            arr.max=a[i];
        sum+=a[i];
        if(a[i]%2==0)
            arr.evenn++;
    }
    arr.avg=sum/n;
    return arr;
}

int main(int argc, const char *argv[])
{
    int i,a[10]={12,34,23,12,35,7,8,2,68,90};
    struct stru aa;
    for (i = 0; i < 10; i++)
    {
        printf("%4d",a[i]);
    }
    printf("\n");
    aa=func(a,10);
    printf("max=%d avg=%.3f evenn=%d\n",aa.max,aa.avg,aa.evenn);
    return 0;
}
5.#用typedef定义一个struct类型
  #typedef 类型 别名   用来给某种类型起别名，不会替换，真正定义了一个类型，多个指针也不会出错。
  # #define 替换名 类型   宏定义  在后面程序中遇到(替换名)替换为(类型)，多个指针时会出错。
#include <stdio.h>

typedef struct person
{
    char name[32];
    char ***[20];
    int age;
}s_t;


int main(int argc, const char *argv[])
{
    int i,n;
    printf("num=");
    scanf("%d",&n);
    s_t a[n];
    printf("enter:name *** age\n");
    for (i = 0; i < n; i++)
    {
        scanf("%s %s %d",&a[i].name,&a[i].***,&a[i].age);
    }
    for (i = 0; i < n; i++)
    {
        printf("%d:%s\t%s\t%d\n",i+1,a[i].name,a[i].***,a[i].age);
    }
    return 0;
}
6.#定义一个如下结构的struct类型，实现输入5个学生的信息，并找出平均成绩最高的打印.
#include <stdio.h>
typedef struct student
{
    int id;
    char name[32];
    int chinese;
    int math;
    int english;
    float average;
} stu_t;
int main(int argc, const char *argv[])
{
    int i,n;
    printf("num=");
    scanf("%d",&n);
    stu_t a[n];
    printf("enter:id name chinese math english\n");
    for (i = 0; i < n; i++)
    {
        scanf("%d %s %d %d %d",&a[i].id,&a[i].name,&a[i].chinese,&a[i].math,&a[i].english);
    }
    stu_t max=a[0];
    for (i = 0; i < n; i++)
    {
        a[i].average=(float)(a[i].chinese+a[i].math+a[i].english)/3;
        if(a[i].average>max.average)
        {
            max=a[i];
        }

    }
    printf("higest average:\n");
    printf("id\tname\tchinese\tmath\tenglish\taverage\n%d\t%s\t%d\t%d\t%d\t%f\n",max.id,max.name,max.chinese,max.math,max.english,max.average);
    return 0;
}