输入年月日输出它是这一年第几天

知识点：学会利用数组和函数解决问题!

思路：年份分为两种平年和闰年，每一月的天数又不尽相同，我们可以定义一个一维数组，确定每一个月的天数.

     

#include<stdio.h>
#include<windows.h>
int hanshu1(int month, int day)
{
	int i, sum= 0;
	int days[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };//定义十三个数让a[1]=31···a[12]=31;
	for (i = 0; i<month; i++)
		sum= sum + days[i];
	return sum + day;
}
int hanshu2(int month, int day)
{
	int i, sum = 0;
	int days[13] = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };	
        for (i = 0; i<month; i++)
		sum = sum + days[i];
	return sum + day;
}
int main()
{
	int year,month,day,t;
	printf("请输入年月日：");
	scanf_s("%d%d%d", &year, &month, &day);
	if ((year % 400 == 0) || (year % 100 != 0 && year % 4 == 0))//判断为闰年
		t = hanshu2(month, day);
	else
		t = hanshu1(month, day);
	printf("这是这一年的第%d天\n", t);
	system("pause");
	return 0;
}

图上为输出结果