I made some changes to the file structure

.gitignore

+*.out
+.DS_Store
+cmake-build-debug
+.idea
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CMakeLists.txt

+cmake_minimum_required(VERSION 3.30)
+project(helloworld)
+
+set(CMAKE_CXX_STANDARD 20)
+
+add_executable(helloworld main.cpp)

main.cpp

+#include <iostream>
+#include <cmath>
+
+int main() {
+    int a, b;
+
+    std::cout << "Enter the lengths of the two sides of the right triangle:" << std::endl;
+    std::cout << "Side a: ";
+    std::cin >> a;
+    std::cout << "Side b: ";
+    std::cin >> b;
+
+    double hypotenuse = sqrt(a * a + b * b);
+
+    std::cout << "The length of the hypotenuse is: " << hypotenuse << std::endl;
+
+    return 0;
+}
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