# include <stdio.h>
# include <malloc.h>
# include <stdlib.h>
struct Students
{
    int Sid;
    char Name[20];
    char Gender;
    float Score;
};
void InputData(struct Students * , int len);
void OutputData(struct Students * , int len);
void Rank(struct Students * , int len );
int main (void)
{
    int len;

    printf ("请输入学生人数：\n");
    printf ("len = ");
    scanf ("%d", &len);

    struct Students * Pst;
    Pst = (struct Students *)malloc(sizeof(struct Students) * len);

    InputData(Pst, len);
    Rank(Pst, len);
    OutputData(Pst, len);


    system("pause");
    return 0;
}

void InputData(struct Students * pst, int len)
{
    int i;
   
    for (i = 0; i < len; i++)
    {
        printf ("请输入第 %d 个学生的信息：\n", i+1);
        printf ("Sid = ");
        scanf ("%d", &pst[i].Sid);
        printf ("Name = ");
        scanf ("%s", pst[i].Name);
        printf ("Gender = ");
        scanf ("%*c%c", &pst[i].Gender);
        printf ("Score = ");
        scanf ("%f", &pst[i].Score);
    }
        
}

void OutputData(struct Students * pst, int len)
{
    int i;
    for(i = 0; i < len; i++)
    {
        printf ("\n\n第 %d 个学生的信息如下：\n", i+1);
        printf ("Sid = %d\n", pst[i].Sid);
        printf ("Name = %s\n", pst[i].Name);
        printf ("Gender = %c\n", pst[i].Gender);
        printf ("Score = %f\n", pst[i].Score);
    }
}
//以下是错的。
void Rank (struct Students * pst, int len)
{
    struct Students st;
    int i;
    for (i = 0; i < len; i++)
    {
        if (pst[i].Score <  pst[i+1].Score)
        {
            st = pst[i];
            pst[i] = pst[i+1];
            pst[i+1] = pst[i];            
        }
   
    }
}
请问我哪错了？使用Rank函数进行冒泡排序

冒泡排序算法复杂度是O（N^2）,也就是说应该是两层嵌套循环

void Rank (struct Students * pst, int len)
{
    struct Students st;
    int i;
    for(int j=0;j<len;j++)
    for (i = j; i < len; i++)
    {
        if (pst[i].Score <  pst[i+1].Score)
        {
            st = pst[i];
            pst[i] = pst[i+1];
            pst[i+1] = pst[i];           

        }
  

    }
}

void Rank (struct Students * pst, int len)
{
    struct Students st;
    int i,j;
    for (i=0; i<len-1; i++)
    {
        for (j=i+1; j<len; j++)
        {
            if (pst[i].Score <  pst[j].Score)
            {
                st = pst[i];
                pst[i] = pst[j];
                pst[j] = st;            
            }
        }
    }
}

[此贴子已经被作者于2017-1-13 09:37编辑过]

谢谢你的指点 得以知道一个知识点

[此贴子已经被作者于2017-1-13 09:51编辑过]

参考吹水佬的吧，，，我的代码不规范，没用花括号括起来，不易于阅读理解

谢谢两位前辈！

[此贴子已经被作者于2017-1-13 09:48编辑过]