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学生课程管理系统,一个学习数据结构过程中的必备程序。

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<string>
#include<iostream>
#include<algorithm>

#define MAXSTD 30 // 开始学生数
#define MAXCLS 5 // 课程数
#define NOTFOUND     if( ( pos = findStd() ) == -1 ){printf( "NOT FOUND!\n" );return -1;} // 自定义宏，处理没有找到学生的情况

using namespace std;


struct STUDENT
{
    int id;
    string name;
    int grd[ 5 ];
};//用于存储学生信息的结构体
STUDENT stdt[ MAXSTD * 10 ]; 
int nSt;

void prtStd( int pos ) // 打印一个学生信息
{
    printf( "The %d th student %s: " , pos + 1 , stdt[ pos ].name.c_str() );
}

void prtGrd( int wh , int pos ) // 打印某学生某门课程成绩
{
    printf( " class %d grade %d.\n\n" , wh  + 1  , stdt[ pos ].grd[ wh ] );
}

void prtAllStd( int crs ) // 打印所有学生某科成绩
{
    int i , j;
    for( i = 0; i < nSt; ++i ){
        prtStd( i );
        if( crs >= 0 && crs <=5 ){
            printf( "couse %d's score is %d \n" , crs + 1 , stdt[ i ].grd[ crs ] );
        }
        else if ( crs == 6 ){
            for( j = 0; j < 5; ++j )
                printf( "couse %d's score is %d\n" , crs + 1 , stdt[ i ].grd[ crs ] );
            printf( "\n" );
        }    
    }    
}

void addAStu( int i ) // 添加一个学生
{
    int j;
    printf( "Enter %dth student's id: " , i + 1 );
    cin >> stdt[ i ].id;
    printf( "\n" );
    printf( "Enter %dth student's name: " , i + 1 );
    cin >> stdt[ i ].name;
    printf( "\n" );
    for( j = 0; j < MAXCLS; ++j ){
        printf( "Enter %dth student's %dth course: " , i + 1 , j + 1 );
        cin >> stdt[ i ].grd[ j ];
        printf( "\n" );
    }
}

void initial_std() // 初始化，读入30个学生的成绩
{
    int i , j ,  k;
    
    printf( "Enter %d students' information:" , MAXSTD );
    nSt = MAXSTD;
    for( i = 0; i < MAXSTD; ++i ){
        addAStu( i );
        printf( "\n" );
    }
//    for( i = 0; i < MAXSTD; ++i ){
//        printf( "%d %s %d %d \n" , stdt[ i ].id , stdt[ i ].name.c_str() , stdt[ i ].grd[ 0 ] );
//    }    
}

int findStd_NAME( string nm ) // 用名字找一个学生
{
    int i , j , k;
    for( i = 0; i < nSt; ++i )
        if( nm == stdt[ i ].name ) return i;
    return -1;
}

int findStd_ID( int id ) // 用id找一个学生
{
    int i , j , k;
    for( i = 0; i < nSt; ++i )
        if( id == stdt[ i ].id ) return i;
    return -1;
}

int findStd() //查找学生
{
    int i , j  , k;
    int tmpId;
    string tmpNm;
    char ch;
    printf( "Enter id or name( I / N ) ?\n" );
    while( 1 ){
        ch = getchar();
        switch( toupper( ch ) ){
        case 'I':
            printf( "Enter id: " );
            cin >> tmpId;
            printf( "\n" );
            return findStd_ID( tmpId );
            break;
        case 'N':
            printf( "Enter name: ");
            cin >> tmpNm;
            printf( "\n" );
            return findStd_NAME( tmpNm );
            break;
        }
    }
    return -1;
}

int addStd() // 所有学生录入完毕后添加一个学生
{
    addAStu( nSt );
    nSt++;
    return 0;
}


int deviseStd() // 修改学生信息
{
    int i , j , k , pos;
    NOTFOUND
        addAStu( pos );
    return 0;
}

int deletPos( int pos ) // 删除学生信息
{
    int i , j , k;
    for( i = pos; i < nSt - 1; ++i )
        stdt[ i ] = stdt[ i + 1 ];
    nSt--;
}

int deletStd() // 定位并删除学生信息
{
    int i ,  j , k , pos;
    if( ( pos = findStd() ) == -1 ){
        printf( "NOT FOUDND!\n" );
        return -1;
    }
    deletPos( pos );
    return 0;
}

int findSbj() // 查找一门课程
{
    int rst;
    printf( "Which subject do you want?\n" );
    cin >> rst;
    return rst;
}

int findClass( int wh ) // 查询某学生的某门课程
{
    int i , j , k , pos;
    NOTFOUND
        prtStd( pos );
    prtGrd( wh , pos );
    return 0;
}

int findAllClass() // 查询所有课程
{
    int i , j , k , pos;
    NOTFOUND
        prtStd( pos );
    printf( "\n" );
    for( i = 0; i < MAXCLS; ++i )
        prtGrd( i , pos );
    return 0;
}

int findAvrg() // 查询学生某科平均分
{
    int i , j ,  k , pos;
    double pt;
    NOTFOUND
        prtStd( pos );
    for( pt = .0 , i = 0; i < MAXCLS; ++i )
        pt += stdt[ pos ].grd[ i ];
    printf( "average grade %lf\n" , pt / 5.0 );
    return 0;
    
}

int findGrdInterval( int wh , int a , int b ) // 查找成绩在某区间的学生
{
    int i ,  j , k;
    printf( "These students satisfy your requirement: \n" );
    for( i = 0; i < nSt; ++i )
        if( stdt[ i ].grd[ wh ] >= a && stdt[ i ].grd[ wh ] <= b ){
            prtStd( i );
            printf( "\n" );
        }    
    printf( "\n" );
    return 0;
}

int sort_GRD( int wh ) // 将所有学生按成绩排序
{
    int i , j  , k;
    STUDENT tmpStd[ MAXSTD * 10 ];
    memcpy( tmpStd , stdt , sizeof( stdt ) );
    for( i = 0; i < nSt; ++i )
        for( j = 0; j < nSt - 1; ++j )
            if( stdt[ j ].grd[ wh ] < stdt[ j + 1 ].grd[ wh ] )
                swap( stdt[ j ] , stdt[ j + 1 ] );
    prtAllStd( wh );
    memcpy( stdt , tmpStd , sizeof( tmpStd ) );
    return 0;
}

int avrgGrd( int wh ) // 某门课程的所有学生的平均分
{
    int i , j  , k;
    double avrg;
    for( avrg = .0 , i = 0; i < nSt; ++i )
        avrg += stdt[ i ].grd[ wh ];
    printf( "average grade %lf\n" , avrg / nSt );
}

int minGrd( int wh ) // 某门课程所有学生的最低成绩
{
    int i , j  , k;
    int minGrd;
    for( minGrd = 0x7fffffff , i = 0; i < nSt; ++i )
        minGrd = min( minGrd , stdt[ i ].grd[ wh ] );
    printf( "min grade is : %d\n " , minGrd );
    return 0;
}

int maxGrd( int wh ) // 某门课程所有学生的最高成绩
{
    int i , j  , k;
    int maxGrd;
    for( maxGrd = 0 , i = 0; i < nSt; ++i )
        maxGrd = max( maxGrd , stdt[ i ].grd[ wh ] );
    printf( "max grade is : %d\n" , maxGrd );
    return 0;
}

int failStdNum() // 所有挂过科的学生
{
    int i , j  , k;
    int rst;
    bool flg;
    for( rst = 0 , i = 0; i < nSt; ++i ){
        flg = false;
        for( j = 0; j < MAXCLS; ++j )
            if( stdt[ i ].grd[ j ] <= 60 ) { flg = true; break;}
        if( flg ) ++rst;
    }
    printf( "There %d students who faild .\n" , rst );
    return 0;
}

void searchStd() // 查询处理主函数
{
    int i , j , k;
    int chs;
    int sbj;
    int a , b;
    do{
        printf( "What do you want to search ? \n" );
        printf( "1.find a student's a given subject's  score .\n" );
        printf( "2.find a student's totol score\n" );
        printf( "3.find a student's average score.\n" );
        printf( "4.find some students whose score is in a given interval.\n" );
        printf( "5.sort by some subject\n" );
        printf( "6.find average score.\n" );
        printf( "7.find highest score.\n" );
        printf( "8.find lowest score.\n " );
        printf( "9.find the number of students who failed.\n" );
        printf( "10.exit\n" );
        cin >> chs;
        switch( chs ){
        case 1: findClass( sbj = findSbj() );break;
        case 2: findAllClass(); break;
        case 3:findAvrg(); break;
        case 4:
            printf( "Please enter the interval ( two numbers: )\n" );
            cin >> a >> b;
            findGrdInterval( sbj = findSbj() , a , b );
            break;
        case 5: sort_GRD( sbj = findSbj() );break;
        case 6: avrgGrd( sbj = findSbj() );break;
        case 7:maxGrd( sbj = findSbj() );break;
        case 8:minGrd( sbj = findSbj() );break;
        case 9:failStdNum();break;
        case 10: return;
        }
    } while( 1 );
}

int main()
{
    int i , j , k , chs;
    int flg;
    int pos;
    initial_std();
    do{//主循环体，等待用户输入选择相应操作
        printf( "What do you want?\n" );
        printf( "1.Add a student\n" );
        printf( "2.Modify a student\n" );
        printf( "3.delete a student\n" );
        printf( "4.search \n" );
        printf( "5.exit\n" );
        cin >> chs;
        flg = 1;
        switch( chs ){
        case 1: addStd(); break;
        case 2: deviseStd(); break;
        case 3: deletStd();break;
        case 4: searchStd(); break;
        case 5: flg = 0; break;
        }
    }    
    while ( flg );
    return 0;
}