Update templates exercise part 2

.gitignore

@@ -9,7 +9,7 @@ exercises/3-containers/part1/test
 exercises/3-containers/part2/test
 exercises/4-pointers/pointers
 exercises/5-templates/part1/sum
-exercises/5-templates/part2/test
+exercises/5-templates/part2/main
 exercises/6.1-my-array/part1
 exercises/6.1-my-array/part2
 exercises/6.1-my-array/part3

exercises/5-templates/README.md

@@ -30,7 +30,9 @@ List the files in `part2`:
 ```bash
 $ cd archer2-cpp/exercises/5-templates/part2
 $ ls
-Makefile  complex.cpp  complex.hpp  test.cpp
+Makefile  array.hpp  main.cpp
 ```
 
-`complex.cpp` contains a working version of the complex number class. Change the class declaration and definitions to use type templating.
+`array.hpp` contains the beginnings of a `FixedSizeArray` class. Update the class declaration and definitions to use type and non-type template parameters. Additionally, add new class member functions as directed by the TODO comments. `main.cpp` provides instructions for trying out and testing your implementation.
+
+As before, you can compile with `make`.

exercises/5-templates/part2/Makefile

@@ -1,10 +1,10 @@
-CXXFLAGS = --std=c++17 -I../../include
+CXXFLAGS = --std=c++20
 
-test : complex.o test.o
+main : main.o
 	$(CXX) $^ -o $@
 
-run : test
-	./test
+run : main
+	./main
 
 clean :
-	rm -rf *.o test
+	rm -rf *.o main

exercises/5-templates/part2/array.hpp

@@ -0,0 +1,27 @@
+#ifndef CPPEX_ARRAY_HPP
+#define CPPEX_ARRAY_HPP
+
+// TODO: Add template parameters to set the data type and array size at compile time
+class FixedSizeArray {
+
+private:
+    int data[10];
+
+public:
+
+    FixedSizeArray() {
+        for (int i = 0; i < 10; ++i) {
+            data[i] = 0;  // Does this work for all data types?
+        }
+    }
+
+    // TODO: Overload the [] operator to provide access to the array elements
+
+    // TODO: Create function size() that returns the size of the array
+
+    // TODO: Create function reduce() that sums all elements of the array
+
+    // TODO: Create function doubleInPlace() that doubles each element of the array
+};
+
+#endif

exercises/5-templates/part2/main.cpp

@@ -0,0 +1,44 @@
+#include "array.hpp"
+#include <iostream>
+
+void print(auto&& arr) {
+    /* Helper function to print the contents of a FixedSizeArray */
+    std::cout << "[ " << arr[0];
+    std::cout << "[ " << arr[0];
+    for (int i = 1; i < arr.size(); ++i) {
+        std::cout << ", " << arr[i];
+    }
+    std::cout << " ]" << std::endl;
+}
+
+int main() {
+    // TODO: Initialise an empty fixed size array of 5 integers
+    std::cout << "Array size: " << arr.size() << std::endl;
+    print(arr);
+
+    // TODO: Use a for loop to set the array values. E.g. 1-5
+    print(arr);
+
+    // TODO: Call doubleInPlace() and print the new array
+    arr.doubleInPlace();
+    print(arr);
+
+    // TODO: Initialise an empty fixed size array of 5 integers with the const specifier
+    print(constArr);
+
+    // TODO: Print the output of calling reduce()
+
+    // TODO: Check you get a compile time error if you try to set an element value in the
+    // const array, or if you call doubleInPlace()
+
+    // TODO: Initialise a fixed size array of strings with element values "Hello" and "World!"
+    print(strArr);
+
+    // TODO: Print the output of calling reduce() on strArr
+
+    // TODO: Call doubleInPlace(). What happens? Can you explain this?
+    // EXTENSION: Can you change the behaviour of doubleInPlace for non numeric data types?
+    // E.g. Just print an error and leave the array unchanged.
+    // Hint: You may want to search for useful type traits, and look up 'if constexpr'.
+    print(strArr);
+}

lectures/5-templates/README.md

@@ -507,8 +507,5 @@ In your clone of this repository, find the `5-templates` exercise. It contains t
 4. Change the `sum()` function to use type templating. How does this change the output?
 
 
-**Part 2**
+**Part 2** - `array.hpp` contains the beginnings of a `FixedSizeArray` class. Add template parameters and complete the tasks in the TODO comments.
 
-`complex.cpp` contains a working version of the complex number class. Change the class declaration and definitions to use type templating.
-
-As before, `test.cpp` holds some basic unit tests and you can compile with `make`.