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c++arraysstlinitialization
Devesh Agrawal
Devesh Agrawal

Reputation: 9212

How to initialize a 2D array with same values in c++

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

Upvotes: 3

Views: 2912

Answers (3)

manlio
manlio

Reputation: 18902

Using fill_n you can write:

std::fill_n(&table[0][0], sizeof(table) / sizeof(**table), 100);

Upvotes: 2

Some programmer dude
Some programmer dude

Reputation: 409176

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.

Upvotes: 1

juanchopanza
juanchopanza

Reputation: 227418

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);

Upvotes: 6

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