自动点名

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动态数组实现自动点名

描述

假设有若干个学生，为了威慑不来上课的同学，欲开发一套自动点名程序，每次课随机抽取若干个学生点名，给出结课后所以学生的出勤分数。

规定

 一共6次课 每个学生出勤满分为5分 如果出现一次缺勤扣1分，两次缺勤扣3分，三次及三次以上扣5分。 常规写法

#include <stdio.h>#include <stdlib.h>#include <time.h>#define MAX 100#define CMAX 4//点名最多次数int InputInfo(char stuName[][20], char stuID[][10]){    int stuNum, i;    printf("Please input the number of students!\n");    scanf("%d", &stuNum);    printf("Please input the information of students!\n");    getchar();//读出缓冲区的空格    for(i=0; i<stuNum; i++)    {        gets(stuName[i]);//gets遇到回车就结束了！        gets(stuID[i]);    }    return stuNum;}void RandomCall(char stuName[][20], char stuID[][10], int stuAbsentNum[], int stuNum){    int i, callNum, callIndex[CMAX];    char answer;    srand(time(NULL));    callNum = rand() % CMAX;    for(i=0; i<callNum; i++)    {        callIndex[i] = rand() % stuNum;        printf("Is the student %s, %s present?\n", stuName[callIndex[i]], stuID[callIndex[i]] );        scanf(" %c", &answer);//读入学生是否出勤，注意在%c前加空格滤除缓冲区的空格！        if(answer == 'n')        {            stuAbsentNum[callIndex[i]]++;        }    }}void SumScore(int stuAbsentNum[], int stuNum, int stuScore[]){    for(int i=0; i<stuNum; i++)    {        switch(stuAbsentNum[i])        {            case 0: stuScore[i] = 5; break;            case 1: stuScore[i] = 4; break;            case 2: stuScore[i] = 2; break;            default: stuScore[i] = 0; break;        }    }}void OutputInfo(char stuName[][20], char stuID[][10], int stuScore[], int stuNum){    for(int i=0; i<stuNum; i++)    {        printf("%s\t%s\t%d\n", stuName[i], stuID[i], stuScore[i]);    }}int main(){    char stuName[MAX][20], stuID[MAX][10];    int stuScore[MAX], stuAbsentNum[MAX]= {0};//后续要在缺勤次数上操作，要初始化！    int stuNum, hours, i;//hours课时数    stuNum = InputInfo(stuName, stuID);    printf("Please input the number of lessons!\n");    scanf("%d", &hours);    for(i=0; i<hours; i++)    {        RandomCall(stuName, stuID, stuAbsentNum, stuNum);    }    SumScore(stuAbsentNum, stuNum, stuScore);    OutputInfo(stuName, stuID, stuScore, stuNum);    return 0;}

动态写法(动态一维数组使用方法)

#include <stdio.h>#include <stdlib.h>#include <time.h>#define MAX 100#define CMAX 4//点名最多次数int InputInfo(char stuName[][20], char stuID[][10]){    int stuNum, i;    printf("Please input the number of students!\n");    scanf("%d", &stuNum);    printf("Please input the information of students!\n");    getchar();//读出缓冲区的空格    for(i=0; i<stuNum; i++)    {        gets(stuName[i]);//gets遇到回车就结束了！        gets(stuID[i]);    }    return stuNum;}void RandomCall(char stuName[][20], char stuID[][10], int stuAbsentNum[], int stuNum){    int i, callNum;    char answer;    int *callIndex;//申请动态空间访问，因为指针和数组是通用的所以采用数组的形式也是合法的访问！    srand(time(NULL));    callNum = rand() % CMAX;    callIndex = (int *)malloc(callNum*sizeof(int));    if(callIndex == NULL)    {        printf("No enough memory!\n");        exit(0);    }    else    {        for(i=0; i<callNum; i++)        {            callIndex[i] = rand() % stuNum; //数组形式            //*(callIndex+i) = rand() % stuNum; //指针形式            printf("Is the student %s, %s present?\n", stuName[callIndex[i]], stuID[callIndex[i]] );            scanf(" %c", &answer);//读入学生是否出勤，注意在%c前加空格滤除缓冲区的空格！            if(answer == 'n')            {                stuAbsentNum[callIndex[i]]++;            }        }    }    free(callIndex);}void SumScore(int stuAbsentNum[], int stuNum, int stuScore[]){    for(int i=0; i<stuNum; i++)    {        switch(stuAbsentNum[i])        {            case 0: stuScore[i] = 5; break;            case 1: stuScore[i] = 4; break;            case 2: stuScore[i] = 2; break;            default: stuScore[i] = 0; break;        }    }}void OutputInfo(char stuName[][20], char stuID[][10], int stuScore[], int stuNum){    for(int i=0; i<stuNum; i++)    {        printf("%s\t%s\t%d\n", stuName[i], stuID[i], stuScore[i]);    }}int main(){    char stuName[MAX][20], stuID[MAX][10];    int stuScore[MAX], stuAbsentNum[MAX]= {0};//后续要在缺勤次数上操作，要初始化！    int stuNum, hours, i;//hours课时数    stuNum = InputInfo(stuName, stuID);    printf("Please input the number of lessons!\n");    scanf("%d", &hours);    for(i=0; i<hours; i++)    {        RandomCall(stuName, stuID, stuAbsentNum, stuNum);    }    SumScore(stuAbsentNum, stuNum, stuScore);    OutputInfo(stuName, stuID, stuScore, stuNum);    return 0;}

再改把里面的二维数组也改成动态申请的形式

#include <stdio.h>#include <stdlib.h>#include <time.h>#define MAX 100#define CMAX 4//点名最多次数void InputInfo(char *pstuName, char *pstuID, int stuNum){    printf("Please input the information of students!\n");    for(int i=0; i<stuNum; i++)    {        gets(pstuName+i*20);//二维数组        gets(pstuID+i*10);    }}void RandomCall(char *pstuName, char *pstuID, int stuAbsentNum[], int stuNum){    int i, callNum;    char answer;    int *callIndex;//申请动态空间访问，因为指针和数组是通用的所以采用数组的形式也是合法的访问！    srand(time(NULL));    callNum = rand() % CMAX;    callIndex = (int *)malloc(callNum*sizeof(int));    if(callIndex == NULL)    {        printf("No enough memory!\n");        exit(0);    }    else    {        for(i=0; i<callNum; i++)        {            callIndex[i] = rand() % stuNum; //数组形式            //*(callIndex+i) = rand() % stuNum; //指针形式            printf("Is the student %s, %s present?\n", pstuName+ callIndex[i] *20, pstuID+ callIndex[i] *10);            scanf(" %c", &answer);//读入学生是否出勤，注意在%c前加空格滤除缓冲区的空格！            if(answer == 'n')            {                stuAbsentNum[callIndex[i]]++;            }        }    }    free(callIndex);}void SumScore(int stuAbsentNum[], int stuNum, int stuScore[]){    for(int i=0; i<stuNum; i++)    {        switch(stuAbsentNum[i])        {            case 0: stuScore[i] = 5; break;            case 1: stuScore[i] = 4; break;            case 2: stuScore[i] = 2; break;            default: stuScore[i] = 0; break;        }    }}void OutputInfo(char *stuName, char *stuID, int stuScore[], int stuNum){    for(int i=0; i<stuNum; i++)    {        printf("%s\t%s\t%d\n", stuName+i*20, stuID+i*10, stuScore[i]);    }}int main(){    //char stuName[MAX][20], stuID[MAX][10];    int stuScore[MAX], stuAbsentNum[MAX]= {0};//后续要在缺勤次数上操作，要初始化！    int stuNum, hours, i;//hours课时数    char *pstuName, *pstuID;    printf("Please input the number of students!\n");    scanf("%d", &stuNum);    getchar();//读出缓冲区的空格    pstuName = (char *)malloc(sizeof(char) *stuNum *20);    pstuID = (char *)malloc(sizeof(char) *stuNum *20);    if(pstuName == NULL || pstuID == NULL)    {        printf("No enough memory!\n");        exit(0);    }    else    {        InputInfo(pstuName, pstuID, stuNum);        printf("Please input the number of lessons!\n");        scanf("%d", &hours);        for(i=0; i<hours; i++)        {            RandomCall(pstuName, pstuID, stuAbsentNum, stuNum);        }        SumScore(stuAbsentNum, stuNum, stuScore);        OutputInfo(pstuName, pstuID, stuScore, stuNum);    }    return 0;}

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