29.结构体求出班级中最高分和学号，将学生信息按照成绩从高到低输出。

1. 一个班不超过40个人，人员信息有成绩和学号组成，班级人数从键盘输入，完成函数，实现求出班级中最高分和学号，将学生信息按照成绩从高到低输出。

#include  <stdio.h>#define ARR_SIZE 40struct student{    int st;    long num;};int findmax(struct student score[],int n,long *pmaxnum){    int i,max;    max=score[0].st;    for(i=0;i<n;i++)        if(max<score[i].st)            max=score[i].st;        *pmaxnum=i;        return max;}void sortscore(struct student *score,int n){    int i,j;    struct student temp1;    for(i=0;i<n-1;i++)        for(j=i+1;j<n;j++)            if (score[i].st<score[j].st)            {                temp1=score[i];score[i]=score[j];score[j]=temp1;                            }   }int main(){    long maxnum;    struct student score[ARR_SIZE];    int maxscore,n,i;    printf("Please enter total number:");    scanf("%d", &n);    /*从键盘输入学生人数n*/    printf("Please enter the number and score:\n");    for(i=0; i<n; i++)  {        scanf("%ld%d", &score[i].num,&score[i].st);    }    maxscore = findmax(score,n, &maxnum);  /*计算最高分及学生学号*/    printf("maxscore = %d, maxnum = %ld\n", maxscore, maxnum);    sortscore(score,n);    printf("The sort after data is :\n");    for(i=0;i<n;i++)        printf("%ld,%d\n",score[i].num,score[i].st);    return 0;}