WE can use fill_n function to initialize 1D array with value.
int table[20];
fill_n(table, 20, 100);
But how can we initialize 2D array with same values.
int table[20][20];
fill_n(table, sizeof(table), 100); //this gives error
3 Answers
You can use a pointer to the first element and a pointer to one past the last one:
int table[20][20];
int* begin = &table[0][0];
size_t size = sizeof(table) / sizeof(table[0][0]);
fill(begin, begin + size, 100);
Comments
Use std::vector:
std::vector<std::vector<int>> table(20, std::vector<int>(20, 100));
All done and "filled" at the declaration. No more code needed.
answered Oct 14, 2014 at 13:29
Some programmer dude
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4 Comments
juanchopanza
Not the same data layout though. They might actually want contiguous data.
leemes
imho, suggesting a whole different alternative should be a comment... You're not answering the question.
Some programmer dude
@leemes It is a solution to the problem stated in the question, that's why I put it as an answer. If there was a way of doing this simple with
std::array that would be even better.leemes
@JoachimPileborg The question only mentions an array. Of course, you were thinking out of the box which is good, and your advice is really good, but still, you're not answering the question. (PS. I'm not the downvoter)
20 * sizeof(int)entries, which is well beyond the bounds of the array.