#include<stdio.h>
#define N 40;
int ReadScore(int score[]);
void DataSort(int score],int n);
void PrintScore(int score[],int n);
int main()
{
    int n,score[N];
    n=ReadScore(score);
    printf("total students are:%d\n",n);
    DataSort(score[],n);
    printf("sorted scores:");
    PrintfScore(score,n);
    return 0;
}
int ReadScore(int score[])
{
    int i=-1;
    do{
        i++;
        printf("input score:");
        scanf("%d",&score[i]);
    }while(score[i]>=0);
    return i;
}
void DataSort(int score[],int n)
int i,j,temp;
{
    for(i=0;i<n-1;i++)
    {
        for(j=i+1;j<n;j++)
        {
            if(score[j]>score[i])
            {
                temp=score[j];
                score[j]=score[i];
                score[i]=temp;
            }
        }
    }
}
void PrintScore(int score[],int n)
{
    int i;
    for(i=0;i<n;i++)
    {
        printf("%4d",score[i]);
    }
    printf("\n");
}

#include<stdio.h>
#define N 40
int ReadScore(int score[]);
void DataSort(int score[],int n);
void PrintScore(int score[],int n);
int main()
{
    int n,score[N];
    n=ReadScore(score);
    printf("total students are:%d\n",n);
    DataSort(score,n);
    printf("sorted scores:");
    PrintScore(score,n);
    return 0;
}
int ReadScore(int score[])
{
    int i=-1;
    do{
        i++;
        printf("input score:");
        scanf("%d",&score[i]);
    }while(score[i]>=0);
    return i;
}
void DataSort(int score[],int n)
{
    int i,j,temp;
    for(i=0;i<n-1;i++)
    {
        for(j=i+1;j<n;j++)
        {
            if(score[j]>score[i])
            {
                temp=score[j];
                score[j]=score[i];
                score[i]=temp;
            }
        }
    }
}
void PrintScore(int score[],int n)
{
    int i;
    for(i=0;i<n;i++)
    {
        printf("%4d",score[i]);
    }
    printf("\n");
}

没看你的程序逻辑，只是编译通过了。如果这个代码是书上的例子，这本书可以直接扔了。

#include<stdio.h>
#define N 40
int ReadScore(int score[]);
void DataSort(int score[],int n);
void PrintScore(int score[],int n);
int main()
{
    int n, score[N];
    n=ReadScore(score);
    printf("total students are:%d\n",n);
    DataSort(score,n);
    printf("sorted scores:");
    PrintScore(score,n);
    return 0;
}
int ReadScore(int score[])
{
    int i=-1;
    do{
        i++;
        printf("input score:");
        scanf("%d",&score[i]);
    }while(score[i]>=0);
    return i;
}
void DataSort(int score[],int n)
{
    int i,j,temp;
    for(i=0;i<n-1;i++)
    {
        for(j=i+1;j<n;j++)
        {
            if(score[j]>score[i])
            {
                temp=score[j];
                score[j]=score[i];
                score[i]=temp;
            }
        }
    }
}
void PrintScore(int score[],int n)
{
    int i;
    for(i=0;i<n;i++)
    {
        printf("%4d",score[i]);
    }
    printf("\n");
}
//那么多报错给得明明白白的，这全是按照编译信息改的。自己多看看编译信息吧。

谢谢

谢谢

int ReadScore(int score[])
{
    int i=-1;
    do{
        i++;
        printf("input score:");
        scanf("%d",&score[i]);
    }while(score[i]>=0);
    return i;
}//
1：循环判断条件有误，没有判断当前输入的个数，有可能造成数组越界，
2：还有当输入小于零的参数结束循环时，本用于结束循环的小于零的参数存入比较数组
3：函数返回值原意是输入参数的个数，实际返回却比实际输入个数小一，例如只有一个输入时，返回值为零
最后，你代码如果真是书上的例子，这书真的可以扔了
修改后：
int ReadScore(int score[])
{
    int i=0;
    int x;
    while(i<N)
    {
        printf("input score:");
        scanf("%d",&x);
        if(x == -1)
        {
            break;
        }
        score[i] = x;
        i++;
    }
    return i;
}