C++ Array Error in Visual Studio

Question

I'm relearning C++ and I'm having some trouble with arrays in classes. Here's a simplified version of what I'm working with

class Class
{
private:
 string array[2];
public:
 Class()
 {
 array[2] = {"Hello", "World"};
 }
 void printOut(int x)
 {
 cout << array[x];
 }

Visual Studio has an error on the first brace in the array initialization in the constructor (i.e. {"Hello", "World"}; which says "Error: expected an expression." However, this problem does not occur when I initialize any other variable (not arrays).

I would have simple initialized the array values when I declared the array in the private section of the class as shown below.

class Class
{
private:
 string array[2] = {"Hello", "World"};

But Visual Studio gives an error on the equals sign saying "Error: data member initialization is now allowed." This error does occur any time I try to initialize the variables at the same time they are declared in the private section of the class.

Any help or advice would be appreciated, thank in advance.

Answer 1

Arrays can only be initialized using that syntax, not assigned. You have to initialize it in the constructor's initialization list:

Class() : array{"Hello", "World"} {}

Alternatively, use std::array which can be assigned.

std::array<string, 2> array;
 Class()
 {
 array = {{ "Hello", "World" }};
 }

---

Another:

Class()
{
 array[0] = "Hello";
 array[1] = "World";
}

• Syntactic Fructose: also, he is attempting to assign those two values to JUST the second element [2]. Array initialization requires there be no element specifier.
• Ben Voigt: @Need4Sleep: He clearly wanted to assign the whole array, and was writing array[2] = because he's used to local variables written as string array[2] = {...}; Pubby's fix is correct.
• Ben Voigt: The parentheses can be removed from the ctor-initializer-list, can't they? Just Class() : array{"Hello", "World"} {}
• Pubby: @BenVoigt Yes, and actually the parenthesis were a compile error. Fixed now.
• gmaster: @Pubby I tried both, neither worked. With the first method, I tried both with and without the parenthesis as Ben Voigt mentioned. I get 3 errors: 1) on the first brace, "Error: expected a "(""; 2) on the end brace "Error: expected a ";"" (adding a ";" did nothing); and 3) on the first brace of the constructor, "Error: expected a declaration." With the second method (std::array) I put the declaration in the private section and initialized it in the constructor; I still get "Error: expected an expression" in the same place.