CODEWITHSUNDEEP
c++arraysinitialization
aki
aki

Reputation: 155

How to initialize a zero array in c++

int M=7;
int N=6;
int i=0;
int x=N*M;
int val3[x] = {};
for(int i=0;i<x;i++)
{
      //some calculations
      if (my condition)
      {
            //if this condition ok, change value of val[i]
      }
      cout << i << "   " << val[i] << endl;
}

I want to initialize a zero array(val), I used above codes, but I got an error which says variable size object may not be initialized. is it not possible to initialize zero array? need your help....thanks

Upvotes: 0

Views: 1024

Answers (3)

joce
joce

Reputation: 9892

Alternatively to the std::vector suggested above, you could also do:

int M=7;
int N=6;
int x=N*M;

int* val3 = new int[x];
memset(val3, 0, x * sizeof (int));
for (int i = 0; i < x; i++)
{
    // ...
}
// ...
delete [] val3;

Upvotes: 0

Potatoswatter
Potatoswatter

Reputation: 137770

C++ does not include variable-length arrays; int val3[ x ] with x non-constant is a feature of C99. Not all C99 features are part of C++. Try using std::vector.

#include <vector>

// contains an array of length x, automatically filled with zeroes
std::vector< int > val3( x );

Upvotes: 4

Xeo
Xeo

Reputation: 131789

int val3[x] = {};

C++ doesn't allow arrays to be initialized with a variable that isn't a compile-time constant. Use a const int for all the variables (except i). Btw, you don't use that first int i (outside the loop).

Upvotes: 3

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