diff --git a/判断素数.cpp b/判断素数.cpp
new file mode 100644
index 0000000..f6b8a91
--- /dev/null
+++ b/判断素数.cpp
@@ -0,0 +1,25 @@
+#include <stdlib.h>
+#include <stdio.h>
+# include<math.h>
+void is_prime(int n)
+{
+ int i = 2;   
+ while (i <= sqrt(n))
+ {
+  if (n%i == 0)
+  {
+   printf("\n %d\n", n);
+   break;  
+  }
+  i++;
+ }
+ if(i > sqrt(n))
+    printf("\n %d\n", n);
+}
+int main()
+{
+ int a = 9;
+
+ is_prime(a);
+ return 0;
+}