c语言 万年历!!

#include "stdio.h"
int isleapyear(int year)
{
   if((year%4!=0||year%100==0) && (year%400!=0) )
     return 0;
   else
     return 1;
}
int firstdayofyear(int year)
{
    return (year+(year-1)/4+(year-1)/400-(year-1)/100)%7;
}
main()
{
    char *monthname[13]={" ","一月份","二月份","三月份","四月份","五月份","六月份","七月份","八月份","九月份","十月份","十一月份","十二月份"};
    int numday_month[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
    int firstday_month[13];
    int workarray[13];
    int year;
	char ch;
    int i,m,n;
	  do
	  {
		  system("cls");                       //清屏效果
	    printf("/n");
		printf("/n");
        printf("                       欢 迎 进 入 万 年 历 查 询 系 统/n");
        printf("/n");
        printf("                              请输入要查询的年份：");
    
		scanf("%d",&year);

        if(isleapyear(year))
           numday_month[2]=29;

        firstday_month[1]=firstdayofyear(year);
    for(i=2;i<=12;i++)
        firstday_month[i]=(firstday_month[i-1]+numday_month[i-1])%7;
    for(i=1;i<=12;i++)
        workarray[i]=-firstday_month[i];

        printf("%34s"," ");
        printf("year %d/n",year);
for(i=1;i<=12;i++)
{
        printf("/n");
        printf("%32s/n/n",monthname[i]);
                                       //printf("%22s"," ");
        printf("星期日/t星期一/t星期二/t星期三/t星期四/t星期五/t星期六/n");
    for(m=1;m<=6;m++)
	{
                                       //printf("%18s"," ");
    for(n=1;n<=7;n++)
	{
        workarray[i]++;
        if(workarray[i]>0&&workarray[i]<=numday_month[i])
           printf("%d/t",workarray[i]);
        else
           printf("/t");
	}
        printf("/n");
	}

	system("pause");
}
        printf("/n是否要继续请按Y/y,按其它键退出系统:");
		scanf(" %c",&ch);
	}while(ch=='Y'||ch=='y');
}