diff --git a/day7/homework/oh2.cpp b/day7/homework/oh2.cpp
new file mode 100644
index 0000000..7184e5a
--- /dev/null
+++ b/day7/homework/oh2.cpp
@@ -0,0 +1,22 @@
+// 输入一个整数，输出它的阶乘。
+// 例如：输入5，输出120
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    int n;
+    int sum = 1;
+    cout << "请输入一个整数：";
+    cin >> n;
+
+    while (n)
+    {
+        sum *= n;
+        --n;
+    }
+    cout << sum << endl;
+
+    return 0;
+}
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