题目：输入某年某月某日，判断这一天是这一年的第几天？
参考程序如下：
#include<stdio.h>void main() {int year, month, day,sum,leap;printf("需要判断的时间（年，月，日）：");scanf("%d,%d,%d", &year, &month, &day);printf("\n");switch (month){case 1:sum = 0; break;case 2:sum = 31; break;case 3:sum = 59; break;case 4:sum = 90; break;case 5:sum = 120; break;case 6:sum = 151; break;case 7:sum = 181; break;case 8:sum = 212; break;case 9:sum = 243; break;case 10:sum = 273; break;case 11:sum = 304; break;case 12:sum = 334; break;default:printf("输入日期格式错误\n");}sum = sum + day;if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {leap = 1;}else{leap = 0;}if (leap == 1 && month > 2) {sum = sum + 1;}printf("这是%d年的第%d天\n", year, sum);}
