VS2013编写C程序,为什么可以不加#include<stdio.h>,也不报错呀?程序如下:
C语言小白,请路过的大神门多多指教,程序如下:main()
{
int day, month, year, sum, leap;
printf("\n please input year,month,day \n");
scanf("%d %d %d", &year, &month, &day);
switch (month) /*先计算某月以前月份的总天数*/
{
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("deta error"); break;
}
sum = sum + day;/*再加上某天的天数*/
if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) /*判断是不是闰年*/
leap = 1;
else
leap = 0;
if (leap == 1 && month > 2)/*如果是闰年且月份大于2,总天数应该加上一天*/
sum++;
printf("It is the %dth day.\n", sum);
}
希望路过的大神能解答来自小白的疑问,在此抱拳啦!
