数据结构 / day02作业

本文介绍: int score;}diff_t;char job;} person_t;int n=3;//定义指针向堆区的内存/*//test}*///输入//计算老师个数//计算学生的平均值//输出//释放堆区空间 return 0;return p;i<n;i++)i<n;count_s++;return -1;int sum=0;i<n;i++)

1. 有若干个学校人员的信息,包括学生和教师。其中学生的数据包括：姓名、性别、职业s/S、分数。教师的数据包括:姓名、性别、职业t/T、职务。 1，定义 指针指向堆区内存 2.循环 输入 3.计算老师的个数 4.计算学生的平均值 5.循环 输出 6·释放堆区 空间

#include <string.h&gt;
#include <stdlib.h&gt;
#include <stdio.h&gt;

typedef union diff
{
    int score;
    char pos[20];

}diff_t;



typedef struct person
{

    char name[20];
    char gender;
    char job;
    diff_t score_or_pos;


} person_t;                                                                                   


person_t *req_mem(int n);
void input(int n, person_t *parr);
int count(char job, int n, person_t *parr);
void output(int n, person_t *parr);
person_t *free_mem(person_t *parr);
float avg(int n, person_t *parr);

int main(int argc, const char *argv[])
{
    int n=3;
    //定义指针向堆区的内存
    person_t *parr=req_mem(n);

    /*//test
      person_t arr_p[]={
      "zhang", 'f', 's', 98,
      "li", 'f', 't', "class teacher",

      "wang", 'm', 't', "schoolmaster",
      "zhao", 'f', 's', 97

      }*/


    //输入
    input(n, parr);


    //计算老师个数
    int teachers = count('t', n, parr);
    putchar(10);
    printf("teacher count=%dn", teachers);

    int students = count('s', n, parr);
    putchar(10);
    printf("students count=%dn", students);


    //计算学生的平均值
    putchar(10);
    float  av=avg(n, parr);
    printf("students avg score=%.2lfn", av);


    //输出
    putchar(10);
    output(n, parr);
                                                                                                                         


    //释放堆区空间
    parr=free_mem(parr);

    return 0;
}

person_t *req_mem(int n)
{
    person_t *p=(person_t*)malloc(sizeof(person_t)*n);
    if(NULL==p)
    {
        printf("error");
        return NULL;
    }

    return p;

}

void input(int n, person_t *parr)                                                                                        
{
    for(int i=0; i<n; i++)
    {
        printf("please input %d name:", i+1);
        scanf("%s", (parr+i)-&gt;name);

        printf("please input  %d gender:", i+1);
        scanf(" %c", &amp;(parr+i)->gender);

        printf("please input %d job:", i+1);
        scanf(" %c", &amp;(parr+i)->job);

        if('s'==((parr+i)->job) || 'S'==(parr+i)->job)
        {

            printf("please input %d score:", i+1);
            scanf("%d", &amp;(parr+i)->score_or_pos.score);

        }

        else if('t'==((parr+i)->job) || 'T'==(parr+i)->job)
        {

            printf("please input %d position:", i+1);
            scanf("%s", (parr+i)->score_or_pos.pos);

        }

    }

}

int count(char job, int n, person_t *parr)
{
    int count_s=0;
    int count_t=0;

    for(int i=0; i<n; i++)
    {

        char cj=(parr+i)->job;
        if(cj=='t'||cj=='T')
        {
            count_t++;
        }
        else if(cj=='s'||cj=='S')
        {
            count_s++;
        }
    }

    if (job=='t'||job=='T')
    {
        return count_t;
    }
    else if('s'==job||'T'==job)
    {
        return count_s;
    }

    return -1;

}      

float avg(int n, person_t *parr)
{
    int sum=0;
    int count=0;
        for(int i=0; i<n; i++)                                                                                           
        {
            char cj = (parr+i)->job;
            if('s'==cj||'S'==cj)
            {
                sum+=(parr+i)->score_or_pos.score;
                count++;

            }
        }

    if(count>0){

        return (float)sum*1.0/count;
    }
    else
    {
        return 0;
    }

}

void output(int n, person_t *parr)
{
    for(int i=0; i<n; i++)
    {
        printf("No. %d person info:n", i+1);
        printf("name=%s, gender=%c, job=%c, ", (parr+i)->name, (parr+i)->gender, (parr+i)->job );
        char cj=(parr+i)->job;
        if('s'==cj||'S'==cj)
        {
            printf("score=%dn", (parr+i)->score_or_pos.score);
        }
        else if('t'==cj||'T'==cj)
        {

            printf("position=%sn", (parr+i)->score_or_pos.pos);
        }

    putchar(10);
    }

    putchar(10);
}

person_t *free_mem(person_t *parr)
{
    if(NULL==parr)
    {
        return NULL;
    }
    free(parr);
    parr=NULL;
    return parr;

}

please input 1 name:w
please input  1 gender:f
please input 1 job:s
please input 1 score:90
please input 2 name:a
please input  2 gender:f
please input 2 job:s
please input 2 score:92
please input 3 name:n
please input  3 gender:f
please input 3 job:t
please input 3 position:class teacher

teacher count=1

students count=2

students avg score=91.00

No. 1 person info:
name=w, gender=f, job=s, score=90

No. 2 person info:
name=a, gender=f, job=s, score=92

No. 3 person info:
name=n, gender=f, job=t, position=class

2. 以下结构体使用 sizeof 计算大小的结果(默认4字节 对齐)

struct s1
{
    char ch;
    int a;
    double b;
    char c1;

};

s1–>20


0x00	ch
0x01
0x02
0x03
0x04	a
0x05
0x06
0x07
0x08	b
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
0x20	c1
0x21
0x22
0x23

写一个简单的宏, 交换A, B两数的值(假设两个变量都是char 或int类型)

struct s2
{
    char ch;
    int a;
    double b;

};

s2–>16


0x00	ch
0x01
0x02
0x03
0x04	a
0x05
0x06
0x07
0x08	b
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F

struct s3
{

    char i;
    struct
    {
        char c;
    };
    
    char a;
    char b;
    char d;
    char e;
    char f;

};

s3->12


0x00	i
0x01
0x02
0x03
0x04	c
0x05	a
0x06	b
0x07	d
0x08	e
0x09	f
0x0A
0x0B

3. 写一个简单的宏，交换两数的值(假设两个变量都是char或int类型)

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#define EXCHANGE a=a+b; b=a-b; a=a-b;                                 


int main(int argc, const char *argv[])
{
    int a=2;
    int b=3;

    printf("before exchange: a=%d, b=%dn", a, b );

    EXCHANGE;
    printf("afterbefore exchange: a=%d, b=%dn", a, b );
    return 0;
}