diff --git a/2207/C语言同步练习/选择结构/4.c b/2207/C语言同步练习/选择结构/4.c
new file mode 100644
index 0000000..7443d2e
--- /dev/null
+++ b/2207/C语言同步练习/选择结构/4.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+
+int main(){
+	
+	int year, month, day, days=0;
+	
+	scanf("%d-%d-%d", &year, &month, &day);
+	days+=day;
+	//1 3 5 7 8 10 12
+	//��ǰһ���¿�ʼ���� 
+	switch(month-1){
+		case 11:days+=30;
+		case 10:days+=31;
+		case 9:days+=30;
+		case 8:days+=31;
+		case 7:days+=31;
+		case 6:days+=30;
+		case 5:days+=31;
+		case 4:days+=30;
+		case 3:days+=31;
+		case 2:days+=28;
+		case 1:days+=31;
+	}
+	if(month>3 && (year%4==0&&year%100!=0 || year%400==0)){
+		days++;
+	} 
+	printf("%d\n", days);
+	
+	
+	return 0;
+}
diff --git a/2207/C语言同步练习/选择结构/4.exe b/2207/C语言同步练习/选择结构/4.exe
new file mode 100644
index 0000000..7c068bf
Binary files /dev/null and b/2207/C语言同步练习/选择结构/4.exe differ