diff --git "a/2109020142/chapter1/\347\254\254\344\272\214\344\270\252\345\256\236\351\252\214" "b/2109020142/chapter1/\347\254\254\344\272\214\344\270\252\345\256\236\351\252\214"
new file mode 100644
index 0000000000000000000000000000000000000000..59a1d229949b31c9e87ac29aa9a06f6e3e6c6c70
--- /dev/null
+++ "b/2109020142/chapter1/\347\254\254\344\272\214\344\270\252\345\256\236\351\252\214"
@@ -0,0 +1,45 @@
+#include <math.h>
+#include <time.h>
+#include <stdio.h>
+int prime(int n)
+{
+    int i,j;
+    int sum;
+    sum=0;
+    int flag;
+    for(i=2;i<n;i++)
+    {
+        flag=1;
+        for(j=2;j<i;j++)
+        {
+            if(i%j==0)
+            {
+                flag=0;
+                break;
+            }
+        }
+        if(flag)
+            sum++;
+    }
+    return sum;
+}
+
+void time(int n)
+{
+    clock_t t,start;
+    int sum;
+    sum=prime(n);
+    start=clock();
+    t=clock()-start;
+    printf("素数个数为%d\n",sum);
+    printf("用时为%lf",((float)t)/CLOCKS_PER_SEC);
+}
+int main()
+{
+    int n;
+    scanf("%d",&n);
+    if(n>100000)
+		return 0;
+    time(n);
+    return 1;
+}
\ No newline at end of file