1 #include <stdio.h>
 2 #include <string.h>
 3
 4 float num[110] = {0};
 5
 6 int main (){
 7 //    freopen ("a.in","r",stdin);
 8 //    freopen ("a.out","w",stdout);
 9
10     int i,n,j;
11     float sum = 0,k;
12
13     i = 0;
14     n = 1;
15     while (1){
16         i++;
17         scanf ("%f",num+i);
18         sum+=num[i];
19
20         char c = getchar();
21         if (c == '\n'){
22             float ping = sum/i;
23             printf ("第%d组的平均数为：%f\n",n,ping);
24
25             for (j = 1,k = 0;j<=i;j++)
26                 k+=(num[j]-ping)*(num[j]-ping);
27             printf ("         方差为：%f\n\n",k/i);
28
29             sum = 0;    n++;    i = 0;
30             memset(num,0,sizeof (num));
31         }
32         if (c == 'E'){
33             return 0;
34         }
35     }
36
37     return 0;
38 }

  1 #include <bits/stdc++.h>
  2
  3 inline void swap(int &a,int &b){
  4     int t = a;a = b,b = t;
  5 }
  6 inline void Gcd (int &aa,int &bb){
  7     int a = aa,b = bb;
  8     if (a<b)
  9         swap (a,b);
 10     int r = a%b;
 11
 12     while (r){
 13         a = b;
 14         b = r;
 15         r = a%b;
 16     }
 17
 18     aa/=b;
 19     bb/=b;
 20 }
 21
 22 void First (int a){
 23     if (abs(a) == 1){
 24         if (a == -1)
 25             std::cout<<'-';
 26     }
 27     else
 28         std::cout<<a;
 29 }
 30 void MLPrint (bool f,int a,int b){
 31     if (f == false)
 32         std::cout<<'-';
 33     else
 34         std::cout<<'+';
 35     std::cout<<a;
 36     if (b != 1)
 37         std::cout<<'/'<<b;
 38 }
 39 void Mid (int a,int b){
 40     int ha = b,hb = 2*a;
 41     bool hf = (ha*hb)>0;
 42     ha = abs(ha),hb = abs(hb);
 43     Gcd(ha,hb);
 44
 45     std::cout<<"(x";
 46     MLPrint(hf,ha,hb);
 47     std::cout<<")^2";
 48 }
 49 void Last (int a,int b,int c){
 50     int ka = 4*a*c-b*b,kb = 4*a;
 51     bool kf = (ka*kb)>0;
 52     ka = abs(ka),kb = abs(kb);
 53     Gcd (ka,kb);
 54
 55     MLPrint (kf,ka,kb);
 56 }
 57
 58 int main (){
 59 //    freopen ("a.in","r",stdin);
 60 //    freopen ("a.out","w",stdout);
 61
 62     int a,b,c;
 63     while (std::cin>>a>>b>>c){
 64         std::cout<<"y = ";
 65         if (abs(a) == 1){
 66             if (a == -1)
 67                 std::cout<<"-";
 68             std::cout<<"x^2";
 69         }
 70         else
 71             std::cout<<a<<"x^2";
 72         if (abs(b) == 1){
 73             if (b == -1)
 74                 std::cout<<"-";
 75             std::cout<<"x";
 76         }
 77         else if (b!=0){
 78             if (b>1)
 79                 std::cout<<'+';
 80             std::cout<<b<<"x";
 81         }
 82         if (c!=0){
 83             if (c>0)
 84                 std::cout<<'+';
 85             std::cout<<c;
 86         }
 87         std::cout<<'\n';
 88         std::cout<<"  = ";
 89
 90         First (a);
 91
 92         if (b == 0 && c == 0){
 93             std::cout<<'\n';
 94             continue;
 95         }
 96         if (b == 0)
 97             std::cout<<"x2";
 98         else
 99             Mid (a,b);
100         Last (a,b,c);
101
102         std::cout<<'\n';
103     }
104
105     return 0;
106 }