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

typedef struct student
{
    long ID;
    float score;
}STU;

void Print(STU s[], int n);
STU * Read(int n);
float Sum(STU s[], int n);
void SortScore(STU s[], int n);
void SortID(STU s[], int n);
void Search(STU s[], int n);
void Analyse(STU s[], int n);

int main()
{
    int n;  //学生数量
    STU *students;
    char key;    //获取按键编号
    float sum,ave;
    printf("Input student number(n<30):\n");
    scanf("%d",&n);
    printf("Management for Students' scores\n1.Input record\n2.Caculate total and average score of course\n3.Sort in descending order by score\n4.Sort in ascending order by number\n5.Search by number\n6.Statistic analysis\n7.List record\n0.Exit\nPlease Input your choice:\n");
    scanf(" %c",&key);
    while(1)
    {
        switch(key)
        {
        case '1':
            students = Read(n);
            break;
        case '2':
            sum = Sum(students, n);
            ave = (float)sum / n;
            printf("sum=%.0f,aver=%.2f\n",sum,ave);
            break;
        case '3':
            SortScore(students, n);
            break;
        case '4':
            SortID(students, n);
            break;
        case '5':
            Search(students, n);
            break;
        case '6':
            Analyse(students, n);
            break;
        case '7':
            Print(students, n);
            break;
        case '0':
            printf("End of program!");
            exit(0);
        default:
            printf("Input error!\n");
        }
        printf("Management for Students' scores\n1.Input record\n2.Caculate total and average score of course\n3.Sort in descending order by score\n4.Sort in ascending order by number\n5.Search by number\n6.Statistic analysis\n7.List record\n0.Exit\nPlease Input your choice:\n");
        scanf(" %c",&key);
    }
    free(students);
    return 0;
}
//打印输出数据
void Print(STU s[], int n)
{
    int i;
    for(i = 0; i < n; i++)
    {
        printf("%ld\t%.0f\n",s[i].ID, s[i].score);
    }
}

//创建数组并赋值
STU * Read(int n)
{
    STU* p;
    int i;
    p = (STU*)malloc(sizeof(STU)*n);
    if(p == NULL)
    {
        printf("Error");
        exit(0);
    }
    printf("Input student's ID, name and score:\n");
    for(i = 0; i < n; i++)
    {
        scanf("%ld%f",&(p[i].ID),&(p[i].score));
    }
    return p;
}
//计算和
float Sum(STU s[], int n)
{
    int i;
    int sum = 0;
    for(i = 0; i < n; i++)
    {
        sum += s[i].score;
    }
    return sum;
}
//按照成绩排序
void SortScore(STU s[], int n)
{
    int i,j;
    STU temp;
    for(i = 0; i < n; i++)
    {
        for(j = 0; j < n-1-i; j++)
        {
            if(s[j].score < s[j+1].score)
            {
                temp = s[j];
                s[j] = s[j+1];
                s[j+1] = temp;
            }
        }
    }
    printf("Sort in descending order by score:\n");
    Print(s, n);
}

void SortID(STU s[], int n)
{
    int i,j;
    STU temp;
    for(i = 0; i < n; i++)
    {
        for(j = 0; j < n-1-i; j++)
        {
            if(s[j].ID > s[j+1].ID)
            {
                temp = s[j];
                s[j] = s[j+1];
                s[j+1] = temp;
            }
        }
    }
    printf("Sort in ascending order by number:\n");
    Print(s, n);
}
void Search(STU s[], int n)
{
    long id;
    int i;
    printf("Input the number you want to search:\n");
    scanf("%ld",&id);
    for(i = 0; i < n; i++)
    {
        if(id == s[i].ID)
        {
            printf("%ld\t%.0f\n",s[i].ID, s[i].score);
            return;
        }
    }
    printf("Not found!\n");
}
void Analyse(STU s[], int n)
{
    int i, score;
    int count[6] = {0};
    for(i = 0; i < n; i++)
    {
        if(s[i].score >= 0 && s[i].score <= 100)
        {
            score = s[i].score / 10;
            switch(score)
            {
            case 0:
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:
                count[0]++;
                break;
            case 6:
                count[1]++;
                break;
            case 7:
                count[2]++;
                break;
            case 8:
                count[3]++;
                break;
            case 9:
                count[4]++;
                break;
            case 10:
                count[5]++;
                break;
            }
        }
    }
    printf("<60\t%d\t%.2f%%\n",count[0], ((float)count[0]/n)*100);
    printf("%d-%d\t%d\t%.2f%%\n", 60, 69,count[1], ((float)count[1]/n)*100);
    printf("%d-%d\t%d\t%.2f%%\n", 70, 79,count[2], ((float)count[2]/n)*100);
    printf("%d-%d\t%d\t%.2f%%\n", 80, 89,count[3], ((float)count[3]/n)*100);
    printf("%d-%d\t%d\t%.2f%%\n", 90, 99,count[4], ((float)count[4]/n)*100);
    printf("%d\t%d\t%.2f%%\n",100,count[5],((float)count[5]/n)*100);
    return;
}