diff --git a/第一讲 变量、输入输出、表达式与顺序语句/604.cpp b/第一讲 变量、输入输出、表达式与顺序语句/604.cpp
new file mode 100644
index 0000000..d38163b
--- /dev/null
+++ b/第一讲 变量、输入输出、表达式与顺序语句/604.cpp	
@@ -0,0 +1,11 @@
+#include <cstdio>
+
+using namespace std;
+
+int main()
+{
+    double pi = 3.14159, r;
+    scanf("%lf", &r);
+    printf("A=%.4f", pi * r * r);
+    return 0;
+}
\ No newline at end of file