diff --git a/class_template.cpp b/class_template.cpp
new file mode 100644
index 0000000..5a0fd4c
--- /dev/null
+++ b/class_template.cpp
@@ -0,0 +1,41 @@
+#include <iostream>
+#include <cmath>
+
+// 用函数模板求解定积分
+class F1
+{
+public:
+    double fun(double x) { return x * x; }
+};
+class F2
+{
+public:
+    double fun(double x) { return x; }
+};
+
+template <typename T>
+class Integrate
+{
+    double a, b;
+    int n;
+    T cf; // 传递被积函数
+public:
+    Integrate(double _a, double _b, int _n = 10000) : a{_a}, b{_b}, n{_n} {}
+    double integrate()
+    {
+        double result{(cf.fun(a) + cf.fun(b)) / 2};
+        double h{(b - a) / n};
+        for (int i{1}; i < n; i++)
+            result += cf.fun(a + i * h);
+        result *= h;
+        return result;
+    }
+};
+
+int main()
+{
+    Integrate<F1> i1{0, 1};
+    Integrate<F2> i2{0, 1};
+    std::cout << i1.integrate() << '\n'
+              << i2.integrate();
+}