Mycode:

compile error,i don't know why?

#include 
     
      #include
      
       #include
       
        #define maxn 10005using namespace std;struct room{    int j;    int f;    double val;};struct room r[3001];bool compare(struct room a,struct room b){  return a.val > b.val;}int main(){    double n,m;    while(cin >> m >> n)    {        if(m == -1&&n == -1)            break;        for(int i = 0;i < n;i ++)        {            cin >> r[i].j;            cin >> r[i].f;            r[i].val = (double)r[i].j/r[i].f;        }        struct room *p = &p[0];        sort(p,p+n,compare);        double ans = 0;        for(int i = 0;i < n&&m > 0;i ++)        {            if(m > r[i].f){                ans += r[i].j;                m -= r[i].f;            }            else{                ans += r[i].j * (m/r[i].f);                m = 0;            }        }        printf("%.3f\n",ans);    }    return 0;}
       
      
     

Correct code:

#include
     
      #include
      
       using namespace std;struct Trade{    int j,f;    double percent;}mouse[3001];bool cmp(Trade a,Trade b){    return a.percent>b.percent;}int main(){    int n,m;    while(scanf("%d%d",&m,&n)!=EOF&&(n!=-1||m!=-1))    {        int i;        for(i=0;i
       
        mouse[i].f)                 {                     sum+=mouse[i].j;                     m-=mouse[i].f;                 }            else                //break;            {                sum+=mouse[i].percent*m;                m=0;                break;            }        }        printf("%.3lf\n",sum);    }    return 0;}