编程练习1.2

C++ primer plus
第六章 编程练习2
“编写一个程序，最多将10个donation值读入到一个double数组中。程序遇到非数字输入时将结束输入，并报告这些数字的平均值以及数组中有多少个数字大于平均值”

 #include<iostream>
 #include<cctype>
 #include<string>
int main()
{
const int SIZE = 10;
bool flag;
int count = 0,num = 0,len = 0;
using namespace std;
string donation;
double group[SIZE] = {0};
double aver = 0,sum = 0;
for(int i = 0;i < SIZE;i++)
{
cout << "Enter number :";
getline(cin,donation);
len = donation.size();
for(int j = 0;j < len;j++)
{
if(!isdigit(donation[j]) && donation[j]!='.' )
{
cout << "Input is not a number." << endl;
i = SIZE;
flag = 0;
break;
}
else
flag = 1;
    }
    if(flag)
    {
        group[i] = stod(donation,0);
        count = i+1;
    }
}    
for(int k=0;k<=count;k++)
{
    sum = sum + group[k];
}
aver = sum/count;
for (int k = 0; k < count; k++)
{
    if(group[k] > aver)
    num++;
}
cout << "average: " << aver <<" There are " << num << " bigger than average." <<endl;
return 0;
}