程序代码：

/*将5位同学3个科目的成绩分别输出，并求出平均分和总分，按总分的大到小排列*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>

/*M必须大于1*/
#define M 5
#define N 5

void input(int scores[][3]);
void cal(int scores[][3], double avgR[], double avgC[]);
void sort(double avgR[], int idx[]);
void printstring(char *s, int n); //打印给定长度的字符串

int main(void)
{
    char *ke[N] = {"语文","数学","英语","平均分","总分"};
    char *names[M] = {"张岚", "李风", "王玉", "赵之风", "田玲"};
    int scores[M][3] = {0}, idx[M] = {0}, i, j;
    double avgR[M] = {0}, avgC[3] = {0};
    input(scores);
    cal(scores, avgR, avgC);
    sort(avgR, idx);
    for(j=0;j<N;j++)
    {
        if(j==0)
            printstring(" ",8);
        printstring(ke[j],8);

 
    }
    printf("\n");
    for (i = 0; i < M; i++)
    {
        printstring(names[i],8);
        for (j = 0; j < 3; j++)
        {
            printf("%3d     ", scores[i][j]); //3位数+5个空格
        }
        printf("%3.1lf    ", avgR[i]); //4位数+4个空格
        printf("%3.0f     \n", avgR[i]*3); //总分=平均分*3
    }
    getchar();
    return 0;
}

void input(int score[][3])
{
    int i, j;
    srand((unsigned) time(NULL));
    for (i = 0; i < M; i++)
        for (j = 0; j < 3; j++)
            score[i][j] = 40 + rand() % 61;
    return;
}
void cal(int scores[][3], double avgR[], double avgC[])
{
    int i, j;
    for (i = 0; i < M; i++)
    {
        for (j = 0; j < 3; j++)
        {
            avgR[i] += scores[i][j];
            avgC[j] += scores[i][j];
        }
        avgR[i] /= 3;
    }
    for (j = 0; j < 3; j++)
        avgC[j] /= M;
    return;
}
void sort(double avgR[], int idx[])
{
    int i, j;

    for (i = 0; i < M; i++)
        idx[i] = i;
    for (i = 0; i < M - 1; i++)
    {
        for (j = i + 1; j < M; j++)
            if (avgR[i] < avgR[j])
                avgR[idx[i]] = avgR[idx[j]];
    }
    return;
}               

void printstring(char *s, int n)
{
    int i=strlen(s),j;
    if(i<=n)
        {
            printf("%s",s);
            for(j=0;j<(n-i);j++)
                printf(" ");
        }
    else
        printf("%8s",s);
}