Structures can be used as types. For example, let's say you want to store data of a car. You could use arrays: int tyreSize[6] = { 10, 20, 30, 40 }; float Height[6] = { 100.5, 130.5, 150.2, 100.0}; string Code[6] = { "Jim", "Tim", "Lin", "Kim"}; And get the data through the index. OR You could create this structure: struct Car { int TyreSize; float Height; string code; }; And create a car: Car car = new Car(); car.TyreSize = 10; etc... Or even cars! Car[] cars = new Cars[7](); Useful resources: geeksforgeeks.org More on reddit.com

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For an "array of arrays" there are no "dimensions" in memory. This is stored as a bunch of arrays packed one after the other, exactly the same as one big array. Either way it has to take your x and y values then do arithmetic to convert that to an actual item. So yeah you do need to index as 100 * y + x for the "flat" array. But let's think about why a array-of-arrays version might be faster. In that version, there's one array containing the address of each sub-array. So the offsets were pre-computed when you made the outer array. So you could try this: make a 10000-element JavaScript array "data", then make a 100-element array "index". Set the values in "index" to be 0,100,200 and so on. Then, access "data" like this: data[index[y]+x] "index" would already contain the pre-multiplied values. See if this is similar in speed to the native JavaScript 2D array. More on reddit.com

is it different across different languages? Yes. More on reddit.com