1108注意单数输出的格式

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
int main()
{	double total = 0;
	int n,sum = 0;
	scanf("%d",&n);
	char s[10000]; 
	for(int i = 0; i < n; i++)
	{
	
		int flag = 1,f = 0,num;
		scanf("%s",s);
		int len = strlen(s);
		for(int j = 0; j < len; j++)
		{
			if((s[j] >= '0' && s[j] <= '9') || s[j] == '.'||s[j] =='-')
			{
				if(s[j] == '.')
				{
					if(f == 0)
					f= 1;
					else 
					{
						flag = 0;
						break;
					}
					num = 0;
				}
				else if((s[j] >= '0' && s[j] <= '9')&& f == 1)
				{
					num++;
					if(num >2)
					{
						flag = 0;
						break;
					}
				}
			}
			else 
			{
				flag = 0;
				break;
			}
		}
	   if(flag)
       {
        	double temp = 0;
        	int i;
       	    for(i = 0; i < len ; i++)
        	{
        		if(s[i] == '-')
        		continue;
       	    	if(s[i] == '.')
       	    	break;
       	    	temp = temp * 10 + (s[i]-'0');
         	}
       	    double a= 0.1;
       	    i++;
       	    if(i != len )
       	    {
       	    	for(i;i < len; i++)
       	    	{
       	    		temp += a * (s[i] - '0');
       	    		//printf("%d\n",s[i] - '0');
       	    		a *= 0.1;
       	    	}
       	    }
       	    if(temp >= -1000 && temp <= 1000)
       	    {
       	    	sum++;
       	    	if(s[0] == '-')	temp = -temp;
			    total += temp;

			   // printf("%f\n",temp);
       	    }
			else printf("ERROR: %s is not a legal number\n",s);
			
       }
	   else 
	   {
	   	printf("ERROR: %s is not a legal number\n",s);
	   }
	}
	if(sum == 0)
	printf("The average of 0 numbers is Undefined\n");
	else if(sum == 1) printf("The average of 1 number is %.2f",total);
	else printf("The average of %d numbers is %.2f",sum,total/sum);
	return 0;
}