Multifile and header guard practise.

main.cpp

@@ -1,25 +1,9 @@
 #include <iostream>
-
-int promptNumber(const char*);
-void addSubTwoNumbers();
+#include "utils.hpp"
 
 int main()
 {
     std::cout << "Add and Subtract 2 Numbers:\n\n";
-    addSubTwoNumbers();
+    utils::addSubTwoNumbers();
     return 0;
 }
-
-int promptNumber(const char* prompt) {
-    int toReturn {};
-    std::cout << prompt;
-    std::cin >> toReturn;
-    return toReturn;
-}
-
-void addSubTwoNumbers() {
-    int num1 {promptNumber("Enter a integer: ")};
-    int num2 {promptNumber("Enter another integer: ")};
-    std::cout << num1 << " + " << num2 << " = " << num1 + num2 << "\n";
-    std::cout << num1 << " - " << num2 << " = " << num1 - num2 << "\n";
-}

utils.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+namespace utils
+{
+int promptNumber(const char* prompt)
+{
+    int toReturn {};
+    std::cout << prompt;
+    std::cin >> toReturn;
+    return toReturn;
+}
+
+void addSubTwoNumbers()
+{
+    int num1 {promptNumber("Enter a integer: ")};
+    int num2 {promptNumber("Enter another integer: ")};
+    std::cout << num1 << " + " << num2 << " = " << num1 + num2 << "\n";
+    std::cout << num1 << " - " << num2 << " = " << num1 - num2 << "\n";
+}
+}

utils.hpp

@@ -0,0 +1,8 @@
+#ifndef utils_H_
+#define utils_H_
+namespace utils
+{
+int promptNumber(const char*);
+void addSubTwoNumbers();
+}
+#endif // utils_H_