求一个日历系统的C语言课程设计

#include <stdio.h>
#include <windows.h>
int week(int y,int m,int d);
void main()
{
int monthday[12]={31,28,31,30,31,30,31,31,30,31,30,31};

int y,w,i,m=1,d=1;
printf("请输入一个年份yyyy：\n");
scanf("%d",&y);
if (y%4==0&&y%100!=0) monthday[1]=29;

for(m=1;m<=12;m++)
{

printf("\n %d年,%d月\n",y,m);
printf("S M T W T F S \n");

for (d=1;d<=monthday[m-1];d++)
{
w=week(y,m,d);
if(d==1)
{
for (i=0;i<w;i++) printf(" ");
}

if(d<10) printf("%d ",d);
else printf("%d ",d);

if(w==6) printf(" \n");
}

}
scanf("%d",&y);
}
int week (int y,int m,int d)
{
int w;