i'm learning objective c , writing program aid people in learning play guitar. wanted create 2d array containing (almost) notes on guitar neck. since there 6 strings on guitar , twelve notes in octave, created 6 x 12 array. edit: solution @ bottom the intention here array read as (string),(fret number) . int strings[6][12] = { { {0, 8},{0, 9},{0, 10},{0, 11} ,{0, 12} ,{0, 1}, {0, 2},{0, 3},{0, 4},{0, 5},{0, 6},{0, 7} }, { {1, 3},{1, 4},{1, 5},{1, 6},{1, 7},{1, 8,},{1, 9},{1, 10},{1, 11} ,{1, 12},{1, 1},{1, 2} }, { {2, 12},{2, 1},{2, 2},{2, 3},{2, 4},{2, 5},{2, 6},{2, 7},{2, 8},{2, 9},{2, 10},{2, 11} }, { {3, 6}, {3, 7} , {3, 8} , {3, 9} ,{3, 10} ,{3, 11} ,{3, 12} ,{3, 1} ,{3, 2} ,{3, 3} ,{3, 4} ,{3, 5} }, { {4, 1} ,{4, 2} ,{4, 3} ,{4, 4} ,{4, 5} ,{4, 6} ,{4, 7} ,{4, 8} ,{4, 9} , {4, 10} ,{4, 11} ,{4, 12} }, { {5, 9},{5, 10},{5, 11} , {5, 12} ,{5, 1},{5, 2},{5, 3},{5, 4},{5, 5},{5, 6},{5, 7},{5, 8} } }; the problem is, xcode throws warning: "e...