输入年月日求是该年的第几天？主函数调用闰年函数，若是闰年返回1否则返回0

#include <stdio.h>

int year(int x,int y,int z){
	int m;
	int d = 0,i,sum=0;
	int a[]= {31,28,31,30,31,30,31,31,30,31,30,31};
	if((x%4==0&&x%100!=0)||x%400==0){
		m =1;
		a[1] = 29;
		for(i = (y-2); 0<=i;i--){
			d +=a[i]; 
		}
	}else{
		m =0;
		for(i = (y-2); 0<=i;i--){
			d +=a[i]; 
		}		
	}
	sum= d+z;
	printf("%d年%d月%d日，是%d的第%d天 \n",x,y,z,x,sum);
	printf("%d \n",m);
	return 0;	
}
	
int main()
{
	int x, y, z;
	printf("请输入年：");scanf("%d",&x); 
		
	printf("请输入月：");scanf("%d",&y);
	while(y>12||y<=0){
		printf("您输入的月份无效，请重新输入：");
		scanf("%d",&y);
	}
	printf("请输入日：");scanf("%d",&z); 
	while(z>31||z<=0){
		printf("您输入的日期无效，请重新输入：");
		scanf("%d",&z);
	}
	year(x,y,z);
	return 0;
}