Return string array in C++ function

Question

I am new to C++. For a school project I need to make a function which will be able to return a string array.

Currently I have this in my header:

Config.h

string[] getVehicles(void); 

Config.cpp

string[] Config::getVehicles(){ string test[5]; test[0] = "test0"; test[1] = "test1"; test[2] = "test2"; test[3] = "test3"; test[4] = "test4";  return test;} 

Obviously this does not work but that's the idea of what I am trying to do. In Java this would be the way to do it. I've tried googling my problem but I didn't come across any answers that were clear to be honest.

Answer 1

Maybe it is better to use a vector in this case, but this is not a correct answer for the question. The reason why it doesn't work is that the variable test just exists in the scope of your function. So you have to manage the memory on your own. Here is an example:

string* getNames() {  string* names = new string[3];  names[0] = "Simon";  names[1] = "Peter";  names[2] = "Dave";    return names; } 

In this case you return a pointer of the position in the heap. All the memory in the heap has to free manually. So it is now your work to delete the memory, if you don't need it anymore:

delete[] names; 

Answer 2

In C++ you don't use an array, but a std::vector instance. Arrays in C++ must have a compile-time fixed length while std::vector instances can change their length at runtime.

std::vector<std::string> Config::getVehicles() {     std::vector<std::string> test(5);     test[0] = "test0";     test[1] = "test1";     test[2] = "test2";     test[3] = "test3";     test[4] = "test4";     return test; } 

std::vector can also grow dynamically, so in a C++ program you will find more often something like

std::vector<std::string> Config::getVehicles() {     std::vector<std::string> test; // Empty on creation     test.push_back("test0"); // Adds an element     test.push_back("test1");     test.push_back("test2");     test.push_back("test3");     test.push_back("test4");     return test; } 

Allocating dynamically an array of std::string is technically possible but a terrible idea in C++ (for example C++ doesn't provide the garbage collector that Java has).

If you want to program in C++ then grab a good C++ book and read it cover to cover first... writing Java code in C++ is a recipe for a disaster because the languages, despite the superficial braces similarity, are very very different in many fundamental ways.