diff --git a/2207/C语言同步练习源码/2.循环结构-4.c b/2207/C语言同步练习源码/2.循环结构-4.c
new file mode 100644
index 0000000..c004d19
--- /dev/null
+++ b/2207/C语言同步练习源码/2.循环结构-4.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+int main(){
+	
+	int i, s, t;//i��������������, s�����洢����λ��,t�ǽ�ȡ�����λ֮����� 
+	for(i=1;i<9999;i++){
+		t = i;
+		while(t > 0){
+			s = (t/10==0?1:(t/100==0?2:(t/1000==0?3:4)));//�����������
+			t = i%(int)pow(10, s-1);//ʹ��ģ��ȥ�����λ 
+			if(t*t == i){
+				printf("%d:%d\n", t, i);
+			}
+		}
+	}
+	
+	
+	
+	return 0;
+}
diff --git a/2207/C语言同步练习答案.md b/2207/C语言同步练习答案.md
index 3b18212..0435360 100644
--- a/2207/C语言同步练习答案.md
+++ b/2207/C语言同步练习答案.md
@@ -253,6 +253,26 @@ int main(){
 ![image-20250220231000056](https://yp.smallkun.cn/markdown/image-20250220231000056.png!compress)
 
 ```c
+#include <stdio.h>
+
+int main(){
+	
+	int i, s, t;//i用来遍历所有数, s用来存储数的位数,t是截取掉最高位之后的数 
+	for(i=1;i<9999;i++){
+		t = i;
+		while(t > 0){
+			s = (t/10==0?1:(t/100==0?2:(t/1000==0?3:4)));//求出这个数字位数
+			t = i%(int)pow(10, s-1);//使用模除去掉最高位 
+			if(t*t == i){
+				printf("%d:%d\n", t, i);
+			}
+		}
+	}
+	
+	
+	
+	return 0;
+}
 ```
 
 ### 循环结构-5