Declare array in C++ header and define it in cpp file?

Question

This is probably a really simple thing but I'm new to C++ so need help. I just want to declare an array in my C++ header file like: ``` int lettersArr[26]; ``` and then define it in a function in the cpp file like: ``` lettersArr[26] = { letA, letB, letC, letD, letE, letF, letG, letH, letI, letJ, letK, letL, letM, letN, letO, letP, letQ, letR, letS, letT, letU, letV, letW, letX, letY, letZ }; ``` but this doesn't work. Have I got the syntax wrong or something? What is the correct way to to this? Thanks a lot.

Accepted Answer

Add `extern` to the declaration in the header file.

```
extern int lettersArr[26];
```

(Also, unless you plan to change the array, consider also adding `const`.)

The definition must have a type. Add `int` (or `const int`):

```
int lettersArr[26] = { letA, /*...*/ };
```

Declare array in C++ header and define it in cpp file?

Solution

Problem