Initializing a two dimensional std vector

Question

So  I have the following   std  vector lt  std  vector  lt int gt   gt  fog    and I am initializing it very naively like       for int i 0  i lt A NUMBER  i                      std  vector  lt int gt  fogRow              for int j 0  j lt OTHER NUMBER  j                                   fogRow push back  0                              fog push back fogRow           And it feels very wrong    Is there another way of initializing a vector like this

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My c   STL code to initialise 5 3 2-D vector with zero    include  lt iostream gt  using namespace std   include  lt vector gt  int main       if we wnt to initialise a 2 D vector with 0       vector lt vector lt int gt  gt  v1 5  vector lt int gt  3 0         for int i 0 i lt v1 size   i               for int j 0 j lt v1 i  size   j                cout lt  lt v1 i  j  lt  lt                   cout lt  lt endl

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The general syntax  as depicted already is     std  vector lt std  vector lt int gt   gt  v  A NUMBER  std  vector  lt int gt   OTHER NUMBER  DEFAULT VALUE       Here  the vector  v  can be visualised as a two dimensional array  with  A NUMBER  of rows  with  OTHER NUMBER  of columns with their initial value set to  DEFAULT VALUE        Also it can be written like this     std  vector  lt int gt  line OTHER NUMBER  DEFAULT VALUE  std  vector lt std  vector lt int gt   gt  v A NUMBER  line    Inputting values in a 2-D vector is similar to inputting values in a 2-D array     for int i   0  i  lt  A NUMBER  i           for int j   0  j  lt  OTHER NUMBER  j               std  cin  gt  gt  v i  j             Examples have already been stated in other answers

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The recommended approach is to use fill constructor to initialize a two-dimensional vector with a given default value    std  vector lt std  vector lt int gt  gt  fog M  std  vector lt int gt  N  default value      where   M and N are dimensions for your 2D vector

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There is no append method in std  vector  but if you want to make a vector containing A NUMBER vectors of int  each of those containing other number zeros  then you can do this   std  vector lt std  vector lt int gt  gt  fog A NUMBER  std  vector lt int gt  OTHER NUMBER

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I think the easiest way to make it done is    std  vector lt std  vector lt int gt  gt v 10 std  vector lt int gt  11 100      10 is the size of the outer or global vector  which is the main one  and 11 is the size of inner vector of type int  and initial values are initialized to 100  That s my first help on stack  i think it helps someone

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Let s say you want to initialize 2D vector  m n  with initial value to be 0  we could do this   include lt iostream gt  int main         int m   2  n   5       vector lt vector lt int gt  gt  vec m  vector lt int gt   n  0         return 0

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Use the std  vector  vector count  value  constructor that accepts an initial size and a default value  std  vector lt std  vector lt int gt   gt  fog      ROW COUNT      std  vector lt int gt  COLUMN COUNT       Defaults to zero initial value  If a value other than zero  say 4 for example  was required to be the default then  std  vector lt std  vector lt int gt   gt  fog      ROW COUNT      std  vector lt int gt  COLUMN COUNT  4     I should also mention uniform initialization was introduced in C  11  which permits the initialization of vector  and other containers  using     std  vector lt std  vector lt int gt   gt  fog     1  1  1                                          2  2  2

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vector lt vector lt int gt  gt  board  for int i 0 i lt m i          board push back          for int j 0 j lt n j              board i  push back 0            This code snippet first inserts an empty vector at each turn  in the other nested loop it pushes the elements inside the vector created by the outer loop  Hope this solves the problem

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Suppose you want to initialize a two dimensional integer vector with n rows and m column each having value  VAL   Write it as     std  vector lt vector lt int gt  gt  arr n  vector lt int gt  m VAL      This VAL can be a integer type variable or constant such as 100

[c++] Initializing a two dimensional std::vector

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