PAT (Advanced Level) 1108. Finding Average (20)

简单模拟。

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<map>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;

char s[1000];
int n;
int num,num2,pos;

bool f()
{
    int p=0;
    for(int i=0;s[i];i++)
    {
        if(s[i]>='0'&&s[i]<='9') continue;
        else if(i==0&&s[i]=='-') continue;
        else if(s[i]=='.') {p++; continue;}
        else return 0;
    }

    if(p>1) return 0;

    pos=strlen(s);
    for(int i=0;s[i];i++) if(s[i]=='.') pos=i;

    int hh=strlen(s)-pos-1;
    if(hh>2) return 0;

    num=0;
    for(int i=0;i<pos;i++)
    {
        if(s[i]>='0'&&s[i]<='9')
            num=num*10+s[i]-'0';
        if(num>1000) return 0;
    }
    if(num>1000) return 0;

    num2=0;
    for(int i=pos+1;s[i];i++)
        num2=num2*10+s[i]-'0';

    double a=1.0*num+num2/(pow(10.0,strlen(s)-pos-1));
    if(a>1000.0) return 0;

    return 1;
}

int main()
{
    scanf("%d",&n);
    double sum=0;
    int  geshu=0;
    for(int i=1;i<=n;i++)
    {
        scanf("%s",s);
        if(f()==0)
            printf("ERROR: %s is not a legal number\n",s);
        else
        {
            double a=0;
            a=1.0*num+num2/(pow(10.0,strlen(s)-pos-1));
            if(s[0]=='-') a=-a;
            sum=sum+a;
            geshu++;
        }
    }
    if(geshu==1)
        printf("The average of 1 number is %.2lf\n",sum);
    else if(geshu==0)
        printf("The average of 0 numbers is Undefined\n");
    else
        printf("The average of %d numbers is %.2lf\n",geshu,sum/geshu);
    return 0;
}