case5排序的值会出现-1和0，case6求的中值不是正确的结果，如何修改

Question

#include <stdio.h>
#include <stdlib.h>
#define SIZE 30  //成绩数组总长度
#include <stdio.h>
#include <stdlib.h>
#define SIZE 30 //成绩数组总长度
#define SEGMENTSIZE 11 //分数段总共有0-10，总计11个段
#define FAILURE -1 //返回失败结果
#define SUCCESS 1 //返回成功结果
#define ASCEND 1 //升序
#define DECEND -1 //降序

int score[SIZE] = { 78, 65, 23, 34, 56, 87, 90, 99, 45, 88, 54, 95, 63, 66, 89, 54, 64, 77, 63, 56, 5, 86, 97, 94, 30, -1 }; //给score[1]到score[25]赋初值。
    unsigned int i,hold,pass;

 
int countStuNum(int array[], int length)
{
    int i, stuNumber = 0;
    for (i = 0; i < length; i++)
        if (array[i] != -1)
            stuNumber++; //因为数组的结尾是-1，统计非-1的个数
        else break;
    
    return stuNumber;
}
 

 
int countMaxScore(int array[], int len)
{
    int max = 0;
    for(int i = 0; i < len; i++)
    {
        if(array[i] >= max)
        max = array[i];
    }
 
    printf("MAX:%d\n", max);
 
    return max;
}
 
int countMinScore(int array[], int len)
{
    int min = 101;
    for(int i = 0; i < len; i++)
    {
        if(array[i] <= min)
        min = array[i];
    }
 
    printf("MIN:%d\n", min);
 
    return min;
}
 
float countAverageScore(int array[], int len)
{
    float ave, sum = 0;
    for(int i = 0; i < len; i++)
    {
        sum += array[i];
    }
    ave = sum / len;
    printf("AVE:%f\n", ave);
 
    return ave;
}
void swap(int *a, int *b){

int t;

t = *a;

*a = *b;

*b = t;

}    

float countMedian(int array[], int len)
{
    float median;
    //冒泡排序
    for(int i=0;i<len;i++)
    {
        median=array[13];
        printf("median:%d\n",median);
    }
    return median;
}
int main()
{
    
 
    //注：数组中有25个学生分数，其中最一个-1表示该元素之前的数组元素值为有效分数。
    int score[SIZE] = { 78, 65, 23, 34, 56, 87, 90, 99, 45, 88, 54, 95, 63, 66, 89, 54, 64, 77, 63, 56, 5, 86, 97, 94, 30,-1}; //给score[1]到score[25]赋初值。
    int i;
    int stuNumber, maxScore, minScore, searchArrayPosition;
    int searchScore, appendScoreNum, insertScoreNum, result, arrayPossition;
    int order;//排序方向
    float averageScore, medianScore;
    enum Status { GAMEOVER, CONTINUE };
    int choiceNum;
    enum Status gameStatus;
    int sortOrder;
 
    int len = countStuNum(score , sizeof(score)/sizeof(int));
    do
    {
 
        gameStatus = CONTINUE;
        printf("\n\t\t学  生  成  绩  管  理  系  统  1.3 \n\t\t\tDesigned by HuangX\n");
        printf("\n\t0.退出程序\t\t\t1.显示所有成绩\n\n");
        printf("\t2.统计最高分\t\t\t3.统计最低分\n\n");
        printf("\t4.统计平均分\t\t\t5.冒泡排序\n\n");
        printf("\t6.成绩中值\t\t\n");
        printf("请选择功能:");
 
        scanf("%d", &choiceNum);
        fflush(stdin);//清除键盘缓冲区的数，否则当输入字符时会出现死循环
 
        switch (choiceNum)
        {
        case 0:
            gameStatus = GAMEOVER;
            
            break;
        case 1:
            for(i=0;i<=24;i++){
            printf("%d\t",score[i]);
            if(i%5==0)
                puts("");
            }

           
            break;
        case 2:
            countMaxScore( score,  len);
            break;
        case 3:
            countMinScore( score,  len);
            break;
        case 4:
            countAverageScore(score,  len);
            break;
        case 5:
            for ( pass = 1; pass < SIZE; pass++ ) { 

      /* loop to control number of comparisons per pass */
      for ( i = 0; i < SIZE - 1; i++ ) {      

         /* compare adjacent elements and swap them if first 
         element is greater than second element */
         if ( score[ i ] > score[ i + 1 ] ) {  
            hold = score[ i ];                   
            score[ i ] = score[ i + 1 ];
            score[ i + 1 ] = hold;
         } /* end if */
      } /* end inner for */
   } /* end outer for */

   printf( "\nData items in ascending order\n" );

 
   for ( i = 0; i < SIZE; i++ ) {
      printf( "%4d", score[ i ] );
   } /* end for */
            break;
        case 6:
             countMedian(score,len);
             break;
        default:
            printf("输入错误，重新输入！\n");
            break;
        }
    }
    while(1);
    return 0;
}

Answer 1

修改处见注释，供参考：

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#define SIZE 30  //成绩数组总长度
#include <stdio.h>
#include <stdlib.h>
#define SIZE 30 //成绩数组总长度
#define SEGMENTSIZE 11 //分数段总共有0-10，总计11个段
#define FAILURE -1 //返回失败结果
#define SUCCESS 1 //返回成功结果
#define ASCEND 1 //升序
#define DECEND -1 //降序
//int score[SIZE] = { 78, 65, 23, 34, 56, 87, 90, 99, 45, 88, 54, 95, 63, 66, 89, 54, 64, 77, 63, 56, 5, 86, 97, 94, 30, -1 };
//给score[1]到score[25]赋初值。
//修改，数组score[] 主函数里已经定义了局部的，这里就没必要再定义一个全局的。
unsigned int i,hold,pass;

int countStuNum(int array[], int length)
{
    int i, stuNumber = 0;
    for (i = 0; i < length; i++)
        if (array[i] != -1)
            stuNumber++; //因为数组的结尾是-1，统计非-1的个数
        else break;

    return stuNumber;
}

int countMaxScore(int array[], int len)
{
    int max = 0;
    for(int i = 0; i < len; i++)
    {
        if(array[i] >= max)
           max = array[i];
    }

    printf("MAX:%d\n", max);

    return max;
}
 
int countMinScore(int array[], int len)
{
    int min = 101;
    for(int i = 0; i < len; i++)
    {
        if(array[i] <= min)
           min = array[i];
    }

    printf("MIN:%d\n", min);
 
    return min;
}
float countAverageScore(int array[], int len)
{
    float ave, sum = 0;
    for(int i = 0; i < len; i++)
    {
        sum += array[i];
    }
    ave = sum / len;
    printf("AVE:%f\n", ave);
 
    return ave;
}
void swap(int *a, int *b){
    int t;
    t = *a;
    *a = *b;
    *b = t;
}
void bbsort(int array[],int len,int order) //修改
{
    int i,j;
    for (i = 0;i < len - 1;i++){
        for (j = 0;j < len - 1 - i;j++){
            if (order ? array[j] > array[j+1] : array[j] < array[j+1])
                swap(&array[j],&array[j+1]);
        }
    }
}
float countMedian(int array[], int len)
{
    float median;
    //冒泡排序
    bbsort(array,len,0);     //修改
    //for(int i=0;i<len;i++) //修改
    //{
        median=(float)array[len/2]; //修改
        printf("median:%f\n",median);//修改
        //printf("median:%d\n",median);
    //}
    return median;
}
void print(int array[],int len) //修改
{
    int i;
    for (i=0;i < len;i++)
    {
        printf((i+1)%10 == 0 ? " %d\n" : (i % 10 == 0 ? "%d" : " %d"),array[i]);
    }   //10 个一行
}
int main()
{
    //注：数组中有25个学生分数，其中最一个-1表示该元素之前的数组元素值为有效分数。
    int score[SIZE] = { 78, 65, 23, 34, 56, 87, 90, 99, 45, 88, 54, 95, 63, 66, 89, 54, 64, 77, 63, 56, 5, 86, 97, 94, 30,-1}; //给score[1]到score[25]赋初值。
    int i;
    int stuNumber, maxScore, minScore, searchArrayPosition;
    int searchScore, appendScoreNum, insertScoreNum, result, arrayPossition;
    int order;//排序方向
    float averageScore, medianScore;
    enum Status { GAMEOVER, CONTINUE };
    int choiceNum;
    enum Status gameStatus;
    int sortOrder;
 
    int len = countStuNum(score , sizeof(score)/sizeof(int));
    do
    {

        gameStatus = CONTINUE;
        printf("\n\t\t学  生  成  绩  管  理  系  统  1.3 \n\t\t\tDesigned by HuangX\n");
        printf("\n\t0.退出程序\t\t\t1.显示所有成绩\n\n");
        printf("\t2.统计最高分\t\t\t3.统计最低分\n\n");
        printf("\t4.统计平均分\t\t\t5.冒泡排序\n\n");
        printf("\t6.成绩中值\t\t\n");
        printf("请选择功能:");
 
        scanf("%d", &choiceNum);
        fflush(stdin);//清除键盘缓冲区的数，否则当输入字符时会出现死循环
 
        switch (choiceNum)
        {
        case 0:
            gameStatus = GAMEOVER;
            break;
        case 1:
            print(score,len);    //修改
                 //for(i=0;i<=24;i++){  修改
                 //rintf("%d\t",score[i]);
                 //if(i%5==0)
                 //    puts("");
                 //}
            break;
        case 2:
            countMaxScore( score,  len);
            break;
        case 3:
            countMinScore( score,  len);
            break;
        case 4:
            countAverageScore(score,  len);
            break;
        case 5:
            //for ( pass = 1; pass < SIZE; pass++ ) { 修改

                 /* loop to control number of comparisons per pass */
                //for ( i = 0; i < SIZE - 1; i++ ) {

                   /* compare adjacent elements and swap them if first
                  element is greater than second element */
                     //if ( score[ i ] > score[ i + 1 ] ) {
                     //    hold = score[ i ];
                     //    score[ i ] = score[ i + 1 ];
                     //    score[ i + 1 ] = hold;
                     //} /* end if */
                //} /* end inner for */
           //} /* end outer for */
           printf("请选择排序方式[0：降序 ，1：升序]:"); //修改
           scanf("%d", &order);
           bbsort(score,len,order);    //修改
           printf( "\nData items in ascending order\n" );
           print(score,len);     //修改
                  //for ( i = 0; i < SIZE; i++ ) {   修改
                  //     printf( "%4d", score[ i ] );
                  //} /* end for */
           break;
        case 6:
             countMedian(score,len);
             break;
        default:
            printf("输入错误，重新输入！\n");
            break;
        }
    }
    while(gameStatus == CONTINUE);//修改 while(1)
    system("pause");
    return 0;
}