diff --git a/example2-3.c b/example2-3.c
new file mode 100644
index 0000000..7652a37
--- /dev/null
+++ b/example2-3.c
@@ -0,0 +1,23 @@
+/*example2-3.c*/
+#include<stdio.h>
+main()
+{	int year,month,day;
+
+	printf("Enter year & month:");
+	scanf("%d%d",&year,&month); /*输入年份和月份*/
+	if (month==2)	/*判断输入的月份是否为二月份*/
+		if ((year%4==0&&year%100!=0)||(year%400==0)) /*是二月份，判断是否为闰年*/
+			day=29;
+		else day=28;
+	else	/*不是二月份，则区分判断各月的天数*/
+		switch (month)
+		{
+			case 1:	case 3:
+			case 5:	case 7:
+			case 8:	case 10:
+			case 12: day=31;	break;		/*多个case公用一个语句*/
+			case 4:	case 6:
+			case 9:	case 11: day=30;	break;
+		}
+	printf("year=%d	month=%d	day=%d\n",year,month,day);
+}