PAT_B1002数字分类

#include<stdio.h>
#include<iostream>
using namespace std;
int main(){
    int a1=,a2=,a3=,a5=;
    double a4=;
    int a4num=;
    int n;
    cin>>n;
    int x,i=;
    while(n--){
        cin>>x;
        switch(x%){
            case :
                if(x%==){
                    a1+=x;
                }
                break;
            case :
                a2+=(i*x);i=-i;//交替求和
                break;
            case :
                a3++;
                break;
            case :
                a4+=(double)x;
                a4num++;
                break;
            case :
                if(x>a5)
                a5=x;
                break;
        }
    }
    (a1>)?(cout<<a1<<" "):(cout<<"N"<<" ");
    (a2!=)?(cout<<a2<<" "):(cout<<"N"<<" ");
    (a3>)?(cout<<a3<<" "):(cout<<"N"<<" ");
    (a4>)?(printf("%.1f ",a4/(double)a4num)):(printf("N "));
    (a5>)?(cout<<a5):(cout<<"N");
    return ;
}