这万年历的代码错哪了？

 #include<iostream>
using namespace std;
#include<iomanip>
int daysofmonth[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int Isleap_year(int year)
{
    if((year%4==0&&year%100!=0)||year%400==0)
        return 1;
    else
        return 0;
}
int get_days(int y,int m,int d)
{
    int i,count=d;  //公年元年1月1日是星期1
    for(i=1;i<y;i++)
    {
        if(Isleap_year(i))
            count++; 
    }
    count+=(365*(y-1));
    if(Isleap_year(y))
        daysofmonth[2]=29;
    for(i=1;i<m;i++)
        count+=daysofmonth[i];
    return count;
}
void printf_year()
{
    system("cls");//清屏 
    int sum,year,month;
    int a[10],b[10];
    cout<<"你想知道哪一年的年历呢？请输入：";
    cin>>year;
    cout<<"======================= The calender of year "<<year<<"========================"<<endl;
    int i=1;
    int j;
    for(i=1;i<=12/3;i++)//每一行显示三个月的月历
    {
        cout<<"----------------------------------------------------------------------------"<<endl;
        for(int h=1;h<=3;h++)
        {
            int m=3*(i-1)+h;
            cout<<"        "<<m<<"月          ";//月份名
        }
        cout<<endl<<"-----------------------------------------------------------------------------"<<endl;
        for( j=0;j<3;j++)
            cout<<"日"<<" 一"<<" 二"<<" 三"<<" 四"<<" 五"<<" 六 "<<"  ";
        cout<<endl;

        for( j=0;j<3;j++)
        {
            month=3*(i-1)+j+1;
            sum=get_days(year,month,1);
            sum=sum%7;
            for(int m=0;m<sum;m++)
                cout<<"   ";
            if(Isleap_year(year))
                daysofmonth[2]=29;
            b[j]=daysofmonth[month];
            for(int k=1;k<8-sum;)
            {
                cout<<setw(2)<<setfill(' ')<<k<<" ";
                k++;
                a[j]=k;
            }
            cout<<"  ";
        }
        cout<<endl;
        for(int w=1;w<=5;w++)
        {
            for(int j=0;j<3;j++)
            {
               int m;
               for(m=1;m<=7;m++,a[j]++)
               {
                   if(a[j]>b[j])
                       break;
                   cout<<setw(2)<<setfill(' ')<<a[j]<<" ";
               }
               for(int n=1;a[j]>b[j],n<=8-m+1;n++)
                   cout<<"  ";
               if(a[j]>b[j]&&m!=8)
                   cout<<"  ";
            }
            cout<<endl;
        }
    }
    cout<<"================================================="<<endl;
}
void main()
{
    printf_year();
    system("pause");
}