diff --git a/class1.cpp b/class1.cpp
new file mode 100644
index 0000000..1a8e6fd
--- /dev/null
+++ b/class1.cpp
@@ -0,0 +1,21 @@
+//奇偶求和
+
+#include<iostream>
+
+using namespace std;
+
+int main(){
+    int n,sum1=0,sum2=0;
+    cin >>n;
+
+    for (int i = 1; i<=n; i+=2)
+    {
+        sum1+=i;
+    }
+    for (int i = 2; i <= n; i+=2)
+    {
+        sum2+=i;
+    }
+    cout <<sum1<<" "<<sum2<<endl;
+    return 0;
+}
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