Added: C++ projects

CPlusPlus/Forward_Declaration/main.cpp

@@ -0,0 +1,22 @@
+#include "functions.h"
+
+void functionB() {} // declared & defined
+void functionC(); // declared
+void functionD(); // declared
+
+int main()
+{
+    // functionA(); // compiler error, because functionA is declared & defined after it is called
+    functionB(); // no error
+    // functionC(); // linker error, because functionC is declared but not defined
+    functionD(); // no error
+    functionE(); // no error
+
+    return 0;
+}
+
+void functionA() {} // declared & defined
+
+void functionD() {} // defined
+
+// void functionE() {} // linker error, because functionE is defined multiple times