Cannot convert Brace-enclosed initializer list

Question

I declare a table of booleans and initialize it in main()

const int dim = 2;
bool Table[dim][dim];

int main(){

     Table[dim][dim] = {{false,false},{true,false}};
     // code    
     return 0;
}

I use mingw compiler and the builder options are g++ -std=c++11. The error is

cannot convert brace-enclosed initializer list to 'bool' in assignment`

Solution 1

Arrays can only be initialized like that on definition, you can't do it afterwards.

Either move the initialization to the definition, or initialize each entry manually.

Solution 2

First, you are trying to assign a concrete element of array instead assigning the full array. Second, you can use initializer list only for initialization, and not for assignment.

Here is correct code:

bool Table = {{false,false},{true,false}};

Comments

[juanchopanza]

You can't assign to plain arrays. You need a type that supports that (std::array<std::array<bool,2>, 2>), or set the elements by hand.

[user1810087]

memset with c++ is never a good approach. use fill instead.

[Ankur]

Well i am embedded developer and we use it almost daily.There is no harm in it i think.

[juanchopanza]

But this doesn't do what OP wants.

[Mike Seymour]

@Shansingh: In this case, memset relies on sizeof(bool)==1, which isn't guaranteed. More generally, it can only be safely used for trivial types, so you're setting up deathtraps to trigger undefined behaviour if the type changes in future. Any decent implementation of std::fill will be as efficient as memset where possible, and will do the right thing when memset won't; so it's better to just use that.

[Ankur]

@juanchopanza :I am just indicating this in term of post initialization.We can use memset in this case.

[mallwright]

Recent versions of GCC warn against the use of memset on class types.