8 算某年某日是某年的第多少天 看似很多，其实都是很简单的判断语句，要有耐心。 Case尽量另起一行更好看，打一段书写一段运行一段 虽然慢但很有感觉{//五花括号{}没有这个就会报错 语法错误 大括号代表的就是你的内容int year,month,day; int sum = 0; int leap = 0;printf("请输入年月日:");scanf_s("%d,%d,%d",&year,&month,&day);printf("year=%d month=%d day=%d\n",year,month,day);switch (month) //()括号里的数字代表下面case几//需要你自行判断需要几个，多了也没事case 1: printf("一月份\n"); sum = 0; break;case 2: printf("二月份\n"); sum = 31; break;case 3: printf("三月份\n"); sum = 59; break;case 4: printf("四月份\n"); sum = 90; break;case 5: printf("五月份\n"); sum = 120; break;case 6: printf("六月份\n"); sum = 151; break;case 7: printf("七月份\n"); sum = 181; break;case 9: printf("九月份\n"); sum = 242; break;case 10: printf("十月份\n"); sum = 273; break;case 11: printf("十一月份\n"); sum = 303; break;case 12: printf("一月份\n"); sum = 334; break;}if (year % 400 == 0 || (year%100==0&&year%4!= 0)){ leap = 1;}else{ leap = 0;}if (leap == 1 && month > 2)//&&且 ||或 ！非 ！||&& 依次顺序{ sum++;}sum = sum + leap;