My current project requires me to fill an array based upon some other values. I know there's the shortcut:

int arr[4][4] = { {0,0,0,0} , {0,0,0,0} , {0,0,0,0} , {0,0,0,0} };

But in this case, I need to fill the array after its declaration. I currently have my code formatted like this:

int arr[4][4];
if(someothervariable == 1){
    arr = { {1,1,1,1},
            {1,2,3,4},
            {2,,3,4,5},
            {3,4,5,6} };
}

But it won't compile. Is there a way to make use of the mentioned shortcut in my case? If not, whats the best fix available? I'd appreciate a way to set it without explicitly assigning each element? ie: arr[0][0] = ...